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I'm still dubious of fully mechanized FW squads as all of your Troops, but I think there's a lot of utility added by one FW squad in a DF.

Consider these situations:
-First turn Night Fight
-Lots of LOS blocking terrain
-Limited cover in your own deployment zone
-You have first turn

In all of these situations, having a single mobile "assault" squad can really help you out. It allows Fire Warriors to quickly get to important places. It allows significant movement turn one when shooting is often suboptimal for small arms. It allows redeployment to more effective positions of fire. It allows redeployment away from threats.

In addition, 12 fire warriors is a pretty hefty payload. They can do a ton of damage in rapid fire range, and they are easily supported by the rest of the Tau army (due to it's long range and good mobility). Think of the mechanized FW squad as concentrated S5. It can put 32 S5 shots anywhere on the board by turn two. It's pretty durable, and it scores, and it's supported by the rest of the Tau army, and all you gave up was 80 points to get guys where they matter the most, with no need to depend on Reserve rolls. You give up the first turn of long range shooting to get double taps where you want them, the rest of the game. Most foot Fire Warriors won't get double taps by the second turn, and probably not the third, so the firepower evens out.

In the worst case scenario, you're fighting an Ork horde, or something like it. There's nowhere to go, and you don't want to get closer. So you start the Fire Warriors on foot, and just use the DF for shoot. It's 80 points for 8 shorter range shots, not so much worse than 81 points for 9 longer range shots in the form of Fire Warriors. But it can also disembark the drones to block assaults, zoom up and get in the way of squads, tank shock, and make a nuisance of itself in a way that you're not hurting to much from the somewhat reduced raw firepower.

dbsamurai wrote:

1) if you need to move and fire your devilfish you're doing something wrong. Devilfishes should fire before or after disgorging troops, not while they're careening around the board. They never had the firepower for that.

When they could fire as if fast they did.

2) they have the exact same cover save they used to have, a 4+ when moving flat out

Naked yes, however under the previous book they could get a 2+ with disruption pods and moving fast.

3) Devilfishes still have higher than normal armor, limiting what can kill them. And considering that dedicated anti tank weapons have always torn through them like tissue paper, the hull points issue isn't a big one (plus don't they have 3 hp?)

They have the same armor as many other dedicated transports, notably Imperial Guard and Eldar transports, and while better armored than Rhinos, after the upgrades most people give them devilfish cost 3x as much as a Rhino to carry around Fire Warriors squads worth half what a Space Marine squad is worth. Meanwhile, you don't need dedicated AT guns to kill devilfish at all, multi-shot mid-strength anti-infantry and middling dual-role weapons like Scatterlasers and Autocannons can bring them down very quickly (or contribute to their destruction much faster than they ever did)

4) They cost the same as they always have

Which is a problem because that cost was originally designed for 2 editions previous where Skimmers were very tough, nigh impossible to kill in CC, Fire Warriors could shoot through them without LoS issues, and everyone else's vehicles were also much more expensive.

with a price decrease for upgrades.

some upgrades.

And once again, you're treating the devilfish like it's a waveserpet or a razorback. It's not, it was never meant to be. It's a tank to carry your guardsmen-with-handcannons in better comparative safety than Imps. Further, you're comparing apples to oranges. Complaining about how you could get more dakka in another slot with the points ignores the fact that no one buys devilfishes for dakka. Devilfishes have never had good dakka What they have had is AV12 on their front face. A very deformed front face that means you can force quite a wide arc to fire at the "front". Let's compare your examples shall we?

So what you're saying is, is that it can't fulfill the role of a Razorback or Wave Serpent, but costs more than gunned-out Razorbacks and almost as much as Wave Serpents, and basically fulfills the role of a 35pt rhino at thrice the price for 1pt higher frontal AV?

Sounds like something has gone wrong here.

Current comparable pricings on Devilfish should put them at 60pts with 10 points for Drone upgrade to SMS and 10 point DPod; This gives you a 12/11/10 Skimmer with 4+ Jink and 3+ Flat-Out, and a semi-decent anti-horde weapon for 90 points.

Compared to the Venom which is 55 points and similar damage output, you're paying 35 points for some survivability, and giving up Fast/Assault/Firepoints.

Giving up firepoints is kind of a hefty price for unit based around having long range, mid strength shooting. And oddly the example of the Venom just shows how badly priced the Dfish is. You're paying almost double, with the only benefit being more armor and losing significant boosts.

As already stated, if you really want troops to do damage turn 2 and be safe turn 1, just get Kroot with a 5 point acute senses upgrade.

 Ailaros wrote:

Siphen wrote:You can have 50 Fire Warriors shooting 50 shots from 30" away...or you can use an Ethereal and 2 Squads in Devilfish and get 70 shots for roughly the same price. Sure, there are downsides. But I don't think footslogging FW is strictly better.

And as for moving firewarriors away from stuff, if your opponent is close enough to target firewarriors with assault, they're likely close enough to target a devil fish with krak grenades. Also, where are you going to run the firewarriors to? Away from an objective, somewhere in the corner a dozen inches away or so? You're just delaying the inevitable.

Also, firewarriors now gain from the army-wide overwatch. You actually WANT your opponent to assault your flimsy speed-bump squads now.

Imagine for a moment, the average playable board. It is 72" on the long edge. If you choose one end of that to put your fire warriors on, then when the assaulty troops come at you, you can move laterally across the long edge of the table to get away from the assaulty troops. Last time I checked, many assault troops have 12" movement and when you combine that with an average 7 on the charge dice, that's 19" range for assault. I don't think krak grenades have that kind of range. You should be relocating your troops when your opponent's assault troops are within 20", not when they are inside 8".

dbsamurai wrote:How can they capture objectives halfway cross the table?

With kroot.

dbsamurai wrote:How do they reposition when an assault squad with JPs closes the gap in two turns?

With crisis suits.

dbsamurai wrote:How do you surivive an army that's actually using template weapons, especially in this edition of plamsa?

With hammerheads and broadsides.

To go back to the scout snipers in a land raider analogy, you're saying that land raiders are good for scouts because it makes them more mobile and durable, while ignoring the fact that there are other things in your codex that do both of those things much, much better.

Making firewarriors bad at what they were good at in order to make them bad at what they were worse at isn't a winning strategy.

archamedius wrote:Imagine for a moment, the average playable board. It is 72" on the long edge. If you choose one end of that to put your fire warriors on, then when the assaulty troops come at you, you can move laterally across the long edge of the table to get away from the assaulty troops. Last time I checked, many assault troops have 12" movement and when you combine that with an average 7 on the charge dice, that's 19" range for assault. I don't think krak grenades have that kind of range. You should be relocating your troops when your opponent's assault troops are within 20", not when they are inside 8".

So... your solution involves preventing the firewarriors from shooting because they're embarked? Firewarriors not shooting are just about as useless as firewarriors in assault. Why even bother taking them then?

Plus, you're looking at movement in a vacuum here. If you move 30" away from fast units, and those fast units were going towards an objective, you just handed the game to your opponent, and he didn't even NEED to kill the firewarriors. Plus, what if your opponent had long-range anti-tank, or had more than one fast unit on the board that was capable of intercepting your pointless firewarriors wherever they were running off and hiding to?

The best solution to firewarriors getting killed is to bring more firewarriors. Learn how to use speedbumps (which tau make exceptional use of with combined overwatch), and you'll do much better than delaying the inevitable in a transport.

I've been playing Mech Tau for a good long while as well, and I still feel it's viable.

Gunline Foot Tau work well, but god do I hate having my guys get hammered by triple Thunderfires and all that other jazz. There's just too much cover ignoring blast / large blast / templates out there - and Firewarriors are simply not survivable enough on foot. To me, then, Mech is about survivability and mobility, not firepower. Instead of losing half your FWs before the enemy gets inside rapid fire range, you simply get maximum concentration of dakka at the right place and time.

Yes, Devilfish no longer get to fire as if they are fast vehicles, and yes that can be a big hit to their gunship talents. But, let's consider: they can cover 18" the first turn flat out, move 6" and disembark 6" on turn 2. That puts your "gunline" anywhere within 30" of where they started, giving you a 45" rapid fire threat range instead of 15". That is when your DFish start adding in their fire support - once they reach the place the need to be.

Of course, there's always the SMS - mobile cover ignoring shots are always good, and having a 36" threat range is a solid one. Great way to clear off small squads holding objectives so that your FWs can take them, or for taking out those pesky Pathfinders.

Survivability wise, DFish are actually pretty tough. AV12 with a 4+ or 3+ cover save, or that 4+ invulnerable against weapons with the Intercept special rule. Sure, they die in CC like any vehicle these days, but your FWs can overwatch in support if needed.

In short, yeah - mech is still viable. It's not something you can just blindly take out for a spin though, your army has to be set up to take advantage of that mobility.

Veskrashen wrote:
I've been playing Mech Tau for a good long while as well, and I still feel it's viable.

Gunline Foot Tau work well, but god do I hate having my guys get hammered by triple Thunderfires and all that other jazz. There's just too much cover ignoring blast / large blast / templates out there - and Firewarriors are simply not survivable enough on foot. To me, then, Mech is about survivability and mobility, not firepower. Instead of losing half your FWs before the enemy gets inside rapid fire range, you simply get maximum concentration of dakka at the right place and time.

Yes, Devilfish no longer get to fire as if they are fast vehicles, and yes that can be a big hit to their gunship talents. But, let's consider: they can cover 18" the first turn flat out, move 6" and disembark 6" on turn 2. That puts your "gunline" anywhere within 30" of where they started, giving you a 45" rapid fire threat range instead of 15". That is when your DFish start adding in their fire support - once they reach the place the need to be.

Of course, there's always the SMS - mobile cover ignoring shots are always good, and having a 36" threat range is a solid one. Great way to clear off small squads holding objectives so that your FWs can take them, or for taking out those pesky Pathfinders.

Survivability wise, DFish are actually pretty tough. AV12 with a 4+ or 3+ cover save, or that 4+ invulnerable against weapons with the Intercept special rule. Sure, they die in CC like any vehicle these days, but your FWs can overwatch in support if needed.

In short, yeah - mech is still viable. It's not something you can just blindly take out for a spin though, your army has to be set up to take advantage of that mobility.

I just don't see most of these points being good enough to make me take Dfish over more firewarriors.

1- Firewarrior in 4+ cover either get cover saves against the Thunderfire cannon, or armor saves against the cover ignoring shot, seems good to me. and if you spread out properly you can reduce the number of models hit down to 3 even 2 models if placed right. Seems like a poor reason to take a Dfish for those points. (btw those points get you 10 FWS)

2-So turn one you get to shoot 0 FWS and 0 shots from the Devilfish as it moves up field. Turn two, you double tap with firewarriors and get one weapon at full BS and the other at snapfire. or you could just take 22 firewarriors instead and shoot both units first and 2nd turn. 30" range and appropriate deployment, means you get shots downfield where you need them. Seems like a total of 44 firewarrior shots over two turns is better then your 28 and 4 snapfire shots.

3- not specifically only you, but everyone lately seems to be quoting SMS at 36", it's only 30" range, and it's a great weapon, but why pay the points for a Dfish to get them, when those points are better spent on a skyray that gets them for free in addition to skyfire, markerlights, and missiles.

4-Why would I ever be concerned with a unit that cannot score/deny, is not real threat in the shooting phase, and if it gets close, dies fairly easy. Durability of this unit doesn't really help as much as people make it out to help. And it's a determent to our low ld firewarriors, if it gets blown up they have to often take both a pinning test and a morale test. seems like a bad plan to me.

5- Imo, mechanized infantry is viable in very small numbers as part of a hybrid force. You are going to need other methods of getting across the field to take objectives. Dfish with lots of flimsy firewarriors in them are just too tempting of targets for opponents and often ties up a lot of your force in failed attempts to cross the board quickly, when you can do a slow and supportive march across the field instead.

Two major issues: First, if you just buy more firewarriors, you rapidly run out of either space or cover to deploy in. Then those template weapons really do cause problems. Second, squads starting on foot are hardly guaranteed good shots first turn. 30" is not 48", or even 36". There will be plenty of boards where you won't have good places to put all your squads due to lack of cover, los blocking terrain, etc. The first turn firewarrior shots can happen, but are not reliable, especially if you're just packing firewarriors in your deployment zone.

 Ailaros wrote:

dbsamurai wrote:How can they capture objectives halfway cross the table?

With kroot.

Kroot are as paper thin as fire warriors, and if you forward deploy them to take objectives they will just get blown off the objective as your opponent walks across the board. You're other options with Kroot are to either 1) keep them in reserves and outflank them, or 2) deploy them and move them up on objectives late game to claim them. Option 1 is what you probably want to do, to harrass the enemy back lines and force him to deal with your kroot instead of other things, and 2 has the same objective claiming issues that foot slogging fire warriors have, they are slow.

 Ailaros wrote:

dbsamurai wrote:How do they reposition when an assault squad with JPs closes the gap in two turns?

With crisis suits.

Crisis suits cannot claim objectives. It is awesome your elites and HQs can stay out of hand to hand and shoot the piss out of enemy assault troops. It is utterly useless to you if your objective scoring units are all dead because they were your speed bumps.

 Ailaros wrote:

dbsamurai wrote:How do you surivive an army that's actually using template weapons, especially in this edition of plamsa?

With hammerheads and broadsides.

No argument here, use anti tank to take out tanks.

 Ailaros wrote:

To go back to the scout snipers in a land raider analogy, you're saying that land raiders are good for scouts because it makes them more mobile and durable, while ignoring the fact that there are other things in your codex that do both of those things much, much better.

Making firewarriors bad at what they were good at in order to make them bad at what they were worse at isn't a winning strategy.

archamedius wrote:Imagine for a moment, the average playable board. It is 72" on the long edge. If you choose one end of that to put your fire warriors on, then when the assaulty troops come at you, you can move laterally across the long edge of the table to get away from the assaulty troops. Last time I checked, many assault troops have 12" movement and when you combine that with an average 7 on the charge dice, that's 19" range for assault. I don't think krak grenades have that kind of range. You should be relocating your troops when your opponent's assault troops are within 20", not when they are inside 8".

So... your solution involves preventing the firewarriors from shooting because they're embarked? Firewarriors not shooting are just about as useless as firewarriors in assault. Why even bother taking them then?

Plus, you're looking at movement in a vacuum here. If you move 30" away from fast units, and those fast units were going towards an objective, you just handed the game to your opponent, and he didn't even NEED to kill the firewarriors. Plus, what if your opponent had long-range anti-tank, or had more than one fast unit on the board that was capable of intercepting your pointless firewarriors wherever they were running off and hiding to?

The best solution to firewarriors getting killed is to bring more firewarriors. Learn how to use speedbumps (which tau make exceptional use of with combined overwatch), and you'll do much better than delaying the inevitable in a transport.

My solution involves using a devilfish to get a firewarrior unit repositioned out of harms way from an assault unit. I said it earlier, you only do this IF you know your combined firepower plus overwatch will not make the assaulty unit manageable. A smart commander for an assault unit will make sure he stays in combat with you during his turn, clears the unit on yours and then gets to assault again on his turn, reducing you to overwatch shooting his unit(s) that are chewing through your lines. Also note that the devilfish gives you the ability to sacrifice the objective early-mid game so you can blow him off it and take it on turn 5. With 18' move you can keep your firewarrior pretty far off the objective to maximize your range but still be in striking distance to claim objectives.

Long story short, Devilfish are far too weak to field competitively on the table, and their points are far too high..

 BrotherOfBone wrote:
Long story short, Devilfish are far too weak to field competitively on the table, OR their points are far too high..

Edit in Bold. They'd be fine at 60-65 points base, or DPod + Supporting Fire as Base imo.

Coyote81 wrote:
I just don't see most of these points being good enough to make me take Dfish over more firewarriors.

1- Firewarrior in 4+ cover either get cover saves against the Thunderfire cannon, or armor saves against the cover ignoring shot, seems good to me. and if you spread out properly you can reduce the number of models hit down to 3 even 2 models if placed right. Seems like a poor reason to take a Dfish for those points. (btw those points get you 10 FWS)

If your FWs are in cover, they're not mobile - and the mobility is what you pay for. In addition, FWs in DFish take exactly 0 wounds from TFCs - far fewer than you take if you're in cover. Yes, you still get your armor saves, but you're going to be making several of them from each round of shooting - you're bound to start failing them sooner rather than later.

2-So turn one you get to shoot 0 FWS and 0 shots from the Devilfish as it moves up field. Turn two, you double tap with firewarriors and get one weapon at full BS and the other at snapfire. or you could just take 22 firewarriors instead and shoot both units first and 2nd turn. 30" range and appropriate deployment, means you get shots downfield where you need them. Seems like a total of 44 firewarrior shots over two turns is better then your 28 and 4 snapfire shots.

IME, you get 22 shots the first turn, and a lot less the second turn - because of casualties you take from enemy shooting. Yes, the math seems to support more shots per point = better, and that's a nice simple way of looking at things. Those simple numbers don't give you the full picture though. 22 shots per turn where your opponent gets to choose what you shoot at, and which are exposed to being degraded by enemy fire in the first place, is worth less strategically than 22 shots rapid where and when you need it. It has to do with the "game is won in the movement phase" theory of 40k.

3- not specifically only you, but everyone lately seems to be quoting SMS at 36", it's only 30" range, and it's a great weapon, but why pay the points for a Dfish to get them, when those points are better spent on a skyray that gets them for free in addition to skyfire, markerlights, and missiles.

36" because of 30" + 6" move. Same way that people see pulse rifles in that way - I don't, because to use that mobility on FWs you have to expose yourself to fire. I always take them on Skyrays and HHs, but those tend to be engaging harder targets that SMS are less effective against. DFish on the other hand are only carrying S5 AP5 shots regardless - might as well make them as effective as possible. SMS allow it to engage targets in cover and support your embarked FWs while allowing your Skyrays and HHs to engage the targets they're best at killing.

4-Why would I ever be concerned with a unit that cannot score/deny, is not real threat in the shooting phase, and if it gets close, dies fairly easy. Durability of this unit doesn't really help as much as people make it out to help. And it's a determent to our low ld firewarriors, if it gets blown up they have to often take both a pinning test and a morale test. seems like a bad plan to me.

FW low LD is a problem all the time, not just when their transport gets blowed up. IME you take far more LD checks sitting in cover or behind an Aegis than you do from wrecked DFish. Besides, if you don't kill / stop the DFish, the FWs inside get where they need to be when they need to be there. You can ignore it, that's fine - and can get tank shocked as needed.

5- Imo, mechanized infantry is viable in very small numbers as part of a hybrid force. You are going to need other methods of getting across the field to take objectives. Dfish with lots of flimsy firewarriors in them are just too tempting of targets for opponents and often ties up a lot of your force in failed attempts to cross the board quickly, when you can do a slow and supportive march across the field instead.

I feel that taking a few vehicles is less reliable than taking several vehicles. Hybrid suffers from offering targets for all your opponent's weapons. Full foot means that his anti-armor weapons are useless. Full mech means his anti-infantry is useless. Hybrid means everything's got an appropriate target it can be effective against.


Automatically Appended Next Post:

 chrisrawr wrote:

 BrotherOfBone wrote:
Long story short, Devilfish are far too weak to field competitively on the table, OR their points are far too high..

Edit in Bold. They'd be fine at 60-65 points base, or DPod + Supporting Fire as Base imo.

They're more expensive than I'd like, that's for sure. But realistically they're good for their points - people just have unrealistic expectations these days. If it's not so ridiculously cheap you cna spam it all to hell, or not so totally invincible as to be a brainless autotake, then obviously it's completely useless and you should never bother to take it.

Try them out - either using them or fighting a fully meched list. They're more survivable and useful than most people give them credit for.

My first lists with the tau dex were FW DF spam. It's simply not as powerful or survivable as using either kroot, or more elites/heavy slots :/

There's definitely a tipping point, above which taking more Mech FWs is detrimental.

Well, that tipping point is 3 units of FW with DF, then.

But even at 1-2 units of FW in/with DF, Kroot are just plain better.

Veskrashen wrote:
I feel that taking a few vehicles is less reliable than taking several vehicles. Hybrid suffers from offering targets for all your opponent's weapons. Full foot means that his anti-armor weapons are useless. Full mech means his anti-infantry is useless. Hybrid means everything's got an appropriate target it can be effective against.

....

They're more expensive than I'd like, that's for sure. But realistically they're good for their points - people just have unrealistic expectations these days. If it's not so ridiculously cheap you cna spam it all to hell, or not so totally invincible as to be a brainless autotake, then obviously it's completely useless and you should never bother to take it.

You said it yourself: If you need to field a mechanized list, you need to spam armour because otherwise you don't achieve target saturation. But at 80-100 points they're just not cheap enough to spam.
The amount you would spend on getting 3 devilfish for a mobile firewarrior army gets you sufficient long range firepower that you don't need the devilfish in the first place.


@ Assault Marines w/ 19" charge.
When assault marines put themselves 19" away from you, the correct response is to move 4" towards them, markerlight them, and rapid fire w/ Ethereal. Running away in your devilfish just leaves open whatever objective you were guarding, deprives you of 2 turns of shooting with 200 points of your army. It would be better just to leave your FW where they are to overwatch (preferably with supporting fire) and hopefully tarpit the enemy for a turn rather than to simply give up ground.

 dbsamurai wrote:

Trasvi wrote:
Devilfish just cost too much now.
1) They can no longer move+fire as if fast, reducing their power and in many cases negating the increases in number of shots that came with 6th ed codex.
2) They don't have nearly as good a cover save as before (5+ when moving at reduced fire power, 4+ with a disruption pod) and it costs them more.
3) Light vehicles are very easy to kill now with the way hull points work. Everyone is moving away from mech in general unless you can spam enough cheap vehicles to achieve target saturation.
4) They cost a lot. Starting at 80, getting to 105 with minimal upgrades, you don't get much firepower from that. Firepower might not be everything, for the same points we can get quite a few mobile support or shooty elements in the army: 2 piranhas with Fusion Blasters. 3 Crisis suits with flamers. 1 Skyfire Broadside. 1 Support Commander... To start running a mechanised list, suddenly you're spending 300 points (1/6) of your army on stuff which is not hugely survivable, not really that mobile and not very good at shooting.

1) if you need to move and fire your devilfish you're doing something wrong. Devilfishes should fire before or after disgorging troops, not while they're careening around the board. They never had the firepower for that.
2) they have the exact same cover save they used to have, a 4+ when moving flat out
3) Devilfishes still have higher than normal armor, limiting what can kill them. And considering that dedicated anti tank weapons have always torn through them like tissue paper, the hull points issue isn't a big one (plus don't they have 3 hp?)
4) They cost the same as they always have, with a price decrease for upgrades. And once again, you're treating the devilfish like it's a waveserpet or a razorback. It's not, it was never meant to be. It's a tank to carry your guardsmen-with-handcannons in better comparative safety than Imps. Further, you're comparing apples to oranges. Complaining about how you could get more dakka in another slot with the points ignores the fact that no one buys devilfishes for dakka. Devilfishes have never had good dakka What they have had is AV12 on their front face. A very deformed front face that means you can force quite a wide arc to fire at the "front". Let's compare your examples shall we?

Piranhas can't carry drones or firewarriors, meaning if they need to rapidly redeploy you're screwed. Crisis suits can't carry anything with them, nor can they survive as well as Devilfishes (since a DF can't be harmed by bolters). And no one buys pure flamer crisis suits because they're only good for throwing into a meatgrinder, and there is enough anti-meatgrinder now to not have to get them. 1 Broadside has inferior dakka, inferior speed, inferior survivablity, and inverior transport capacity.

Are you seeing a pattern? None of your examples fill the same role as a Devilfish in that none of them can actually get your scoring units where they need to be.

Just nitpicking here but Dpods were formerly shroud, not stealth, so they gave a 3+ pre the new codex. so long as the skimmer had moved.
"Page 30 – Armoury, Disruption Pod.
Change the last sentence to read “A vehicle with a disruption
pod has the Shrouded special rule against any weapons firing
from more than 12" away.”" (old FAQ)

Trasvi wrote:

Veskrashen wrote:
I feel that taking a few vehicles is less reliable than taking several vehicles. Hybrid suffers from offering targets for all your opponent's weapons. Full foot means that his anti-armor weapons are useless. Full mech means his anti-infantry is useless. Hybrid means everything's got an appropriate target it can be effective against.

They're more expensive than I'd like, that's for sure. But realistically they're good for their points - people just have unrealistic expectations these days. If it's not so ridiculously cheap you cna spam it all to hell, or not so totally invincible as to be a brainless autotake, then obviously it's completely useless and you should never bother to take it.

You said it yourself: If you need to field a mechanized list, you need to spam armour because otherwise you don't achieve target saturation. But at 80-100 points they're just not cheap enough to spam.
The amount you would spend on getting 3 devilfish for a mobile firewarrior army gets you sufficient long range firepower that you don't need the devilfish in the first place.

Guess we have different definitions of spamming, or what is needed for target saturation. If I've got 2-3 squads of FW in DFish, 2 Hammerheads and a Skyray, that's 5-6 AV12+ platforms on the board, and no squishy infantry to shoot at - at least until you crack open those DFish. As long as whatever else you're fielding is sufficiently tough or tricksy to get at (Riptides, JSJ Crisis, outflankers, etc) then you've achieved the original objective of denying your opponent stuff to shoot at. I don't have to put 6+ meched infantry squads on the board to achieve that kind of target denial / saturation.

@ Assault Marines w/ 19" charge.When assault marines put themselves 19" away from you, the correct response is to move 4" towards them, markerlight them, and rapid fire w/ Ethereal. Running away in your devilfish just leaves open whatever objective you were guarding, deprives you of 2 turns of shooting with 200 points of your army. It would be better just to leave your FW where they are to overwatch (preferably with supporting fire) and hopefully tarpit the enemy for a turn rather than to simply give up ground.

My preferred method is to not be "guarding" an objective if I don't absolutely have to in the first place, thus I'm not tied to one spot spatially. The correct response in my book is to markerlight them up and drop some Ion Cannon shots or Seeker Missiles on them, and polish them off with SMS fire. Small squads like that don't need FW rapid fire to clear off, and we can take enough AP3 shooting cheaply and easily that you don't have to rely on volume of fire from FWs to get the job done. You can save the FWs for other targets.

Edit:
If you're going to play mech, you really kind of have to commit to a mech army, and not try to hybrid it up - at least when it comes to mechanized infantry. In addition, you have to play very very differently than you would if you were playing a primarily foot based army - mechanized infantry have to play mobility warfare, and not the usual attrition style. Mech Tau in particular is a lot more expensive - points wise - to pull off than other mechanized lists, and the nature of our transports and troops means you have to play it very very differently.

With Psyback Spam GK, for example, your goal is to put as many cheap transports with S6 guns on the board. Mech IG is similar, but the Chimeras are mostly flamer caddies holding melta/plasma/lascannons more than anything. In both these cases, you're taking the transports either because they're the source of firepower, or they're a way to get your special/heavy weapons in range where they can do their job before your dudes with crappy toughness and armor get pasted by all the anti-infantry weapons out there. Tau transports aren't cheap enough to justify taking for their firepower, and the guns they carry aren't really special in the Tau army as you can get S5 AP5 anywhere very cheaply. Your troops inside aren't armed with anything special either - just more S5 AP5, and can't shoot out of the transport anyway. Tau transports are therefore a whole lot more like Eldar Wave Serpents than anything else - a way to keep your dudes safe and sound until you drop them off where they'll do the most good. With Eldar, that's generally Fire Dragons getting ready to nuke a tank; with Tau, that's going to be light infantry, or holding an objective you've cleared by fire from the rest of your army. Mech Tau don't play the way other armies do, and it's going to be a bit before we see really skilled mech tau players out there who can demonstrate their potential since it does require a different point of view.