I wouldn't take the advice about the airburst going into a suicide squad. With killpoints factoring in so heavily, I also wouldn't take a suicide squad. I'll tell you this though:
Metagame or non metagame...vehicles are what people are doing. You're SERIOUSLY lacking anti-tank. Your suits are middle of the road without any specialty, and your army is comprised of a mish-mash of things that aren't going to fit well together as an "army" on the table. You've got a collection of units, who are going to be doing their own thing, without a larger coordination and "army" sense going on. Does that make sense? Here's my two cents:
1. Anti-tank. Get more. You have 89,745,897,623,987,635 ways to deal with genestealers and foot-slogging orks as a tau player. Your submunition round doesn't scare anyone else. As anti-tank, that single shot is more likely than not to not do anything. Please, please please please....drop a railhead and pick up 3 more broadsides. They're magical, and will be even more-so in this 'Ard Boyz. Honestly, your third heavy support should probably even be 3 more broadsides, or a 3 sniper teams. =p
2. Your boradsides should have smart missiles instead of plasma. If stuff is close enough to plasma, you're in trouble, and if you're dropping plasma on non-vehicles that are closing on you even when there are vehicles needing to be popped, you're wasting broadside shots. Better to use something else to come in screening your broadsides. Save yourself the points.

I've played Tau for a good while, and have done incredibly well with them - opportunities to use both weapons just don't really show up. I'd drop the multi-trackers and pick up Adv.
SS, it gives you mobility.
3. As previously mentioned, you *do* need more troop choices. In 'Ard Boyz, you *NEED* to stomp your opponents to do well. If you run into the first scenario with 5 objectives, and you only have 3 troop choices to start...your enemy has 2500 points to make sure your 280 points dies. 2500 points vs 280 points. Even if you have units of 6 firewarriors, you've got to have more, and you want them in devilfish, protected.
4. Don't use
deathrain or
fireknife configurations just because they're popular.
Deathrain suits are nice for taking down transports, but you need to evaluate if that's a weakness in your army before you commit to them. Likewise, what purpose do your
fireknife suits serve? Honestly, its a terrible combination. One is long range, one is short range...*gags* Try Fusion/Plasma. For some real hurt, make them a bodyguard so that everyone gets wargear; then you can take multi-tracker+targeting arrays. You now have a bonafide
MEQ, Terminator, Vehicle killing, mobile unit that can screen stuff and nuke *anything*. Tack in a few shield drones, and you're golden. Whatever you do, make every unit fill a hole in your strategy. Your suits are currently weak and lacking.
5. Small point here, but a stimpack is going to be more effective on another suit than your Shas'o with his Iridium armor. You won't fail your 2+ often enough to justify him having it, and the other half of the time, he won't get his armor save from AP1 and AP2 weapons (or STR8+). Give it to a suit with a 3+; gives you a good chance of getting your points out of it. Stimpack doesn't really make Shas'o with Iridium armor more survivable.
6. Did I mention that you need more troop choices? As is, I can't really think of any army that won't make you lose round 1. 2500 points vs 280 points, and you've pretty much auto-lost unless you can do the same to your opponent *AND* contest the objectives up close and personal....as tau....*laughing*
7. Fast attack count as 2
KP, and you have 4 *very* easy killpoints right there. Please, lose them and get more firewarriors.
8. Speaking of firewarriors....if someone concentrates on a squad of your firewarriors, they're going to take a beating, whether you have 8 or 12 of them. If points are an issue, run with 6 (minimum size possible) and stick them in devilfish...which you should add flechette launchers to.
9. I think your
HQs have really ugly weapon configurations.
TL fusion blasters....eww. You should have railguns to deal with that. Fusion blasters should be Nob/Terminator/
MEQ killing weapons.
10. Wound allocation and you: You need to use it. Every suit in a squad should be equipped a little differently than others if you can for wound allocation, so that you can take a few wounds without losing a model (since they're equipped differently and are different wound groups). Its easy; just drop a blacksun filter onto someone and voila; they're their own wound group.
11. Stealthsuits: Do they belong in your list? Do you have a place for them? What's their purpose? Tau are a finesse army. Everything has to work together like a well-oiled machine for you to succeed; you can't have a bunch of independent units on the board that aren't part of a larger strategic vision.
12. Your Shas'o doesn't need a target lock; he's by himself!
That's my advice for you. My quick and dirt list (not going to try adding points) but here's what I'd do in your shoes:
HQ: Shas'o - airbursting frag launcher+(pick a second weapon), Iridium armor, 2 shield drones. This is your "bait" unit. Drop Shas'o in cover, and he's got a 2+ armor save, two shield drones to drop invul saves on if required, a 4+ cover save, and he's nigh unkillable. I wouldn't take a POS relay; trying ninja tau trickery is going to get you spanked in 'Ard Boyz, and is a bad idea to start with. The whole STRENGTH of Tau is massed firepower, and you're giving it up and presenting your army piecemeal to be eaten if you try the POS relay stuff. Worse, if you come up against
IG with fleet commanders in the
HQ retinue, they each add +1 to your reserve rolls. There's going to be *LOTS* of
IG this year as people dust off their armies with the new codex. You're going to need 4+ to get one unit per turn instead of a 2+. Which still feeds your army one unit at a time to the enemy.
HQ2: Shas'o or
el, with the two bodyguards I discussed earlier, with fusion/plasma
Troop 1: 6
FW, Shas'ui / Devilfish+Disruption Pods, Flechette launchers, multi-tracker
Troop 2: Same
Troop 3: Same
Troop 4: Same
If you have more points....troop 5 and 6.
Fast attack 1: 8 Pathfinders, 3 Railrifles (they can all shoot different units and cause 3 separate pinning checks!) + Devilfish
Elite 1: 3
Deathrain suits+2 gun drones (equip them differently...don't use flamers. =p
Elite 2: Either go with Fusion/Plasma, or combine some
MEQ killing elements of
TL plasma in here.
Heavy 1: 3 Broadsides, previously discussed
Heavy 2: 3 Broadsides, previously discussed
Heavy 3: Snipers or a railhead.
That army list can pretty much kill anything. You've got your shas'o dishing out cover ignoring horde control, your devilfish with huge mobility capable of doing the same with their burst cannons, gun drones, and rapid firing firewarriors if need be, and there's nothing like charging your devilfish into orks and getting them to assault it, while causing 15 wounds on them for doing so. Ork anti-tank consists of assaulting vehicles. Make them pay for it.
The broadsides can take down potentially 4 tanks per turn. If you deal with the armor, they can turn on monstrous creatures, terminators, obliterators....anything expensive.

The rest of your army is support for this core idea. The suits in here have devestating firepower...all that AP1 and AP2 means anything you look at dies, and you can use markerlights to ensure hits. 2+ to hit, 2+ to wound, no armor saves? Yes please!
You can make a mobile list instead if you like, but this year vehicles are the way to go, and anti-tank will rule the field.
Automatically Appended Next Post: *rubs his eyes*
Holy moley that was a long post.