Okay, so we're having to go off of a ton of rumors here so everything must be taken with a grain of salt.
Still, I thought I'd slap up some quick statistics to wet the would-be eldar general's appetite and to get people looking at what the future will hold for tactics.
First off, the much-maligned Dire Avenger. I ran some numbers on pts of Meq kills per Dire Avenger based off of a number of different 'buffs' in the form of rumored Farseer powers, Exarch abilities, etc...
Normal shooting: 2 shots, 4/3 hits, 2/3 wounds, 2/9 dead = 3.33 pts of dead Meq
Rumored Shuriken Storm: 3 shots, 2 hits, 1 wound, 1/3 dead = 5 pts of dead Meq
'Doomstorm' (Doom psychic power + Shuriken Storm): 3 shots, 2 hits, 3/2 wounds, 1/2 dead = 7.5 pts of dead Meq
'Guidestorm' (Guide + Shuriken Storm): 3 shots, 20/9 hits, 10/9 wounds, 10/27 dead = 5.55 pts of dead Meq
'Uberstorm' (Guide + Doom + Shuriken Storm): 3 shots, 20/9 hits, 15/9 wounds, 15/27 dead = 8.55 pts of dead Meq
Interesting, the biggest gain here is if you manage to Shuriken Storm a Doomed Meq unit - giving each member of the squad a 50/50 shot of taking out a Meq. Those are damned good stats for a basic trooper armed with standard weaponry. It seems that Farseers will truly give a <st1:place w:st="on">LOT</st1:place> of power to the list in the form of making units that much better, acting as a nice force multiplier.
Now, Warp Spiders
Normal shooting: 2 shots, 4/3 hits, 10/9 wounds, 10/27 dead = 5.55 pts dead Meq (notice anything? It's the same as for the 'Guidestorm' listing above)
Shooting w/Guide: 2 shots, 16/9 hits, 40/27 wounds, 40/81 dead = ~7.41 pts dead Meq
I didn't even bother with the Doom scenario as, quite frankly, it would have minimal impact (the squad already wounds on a 2+, so all Doom gives you is the re-roll on the few 1's that would actually come up. Trust me, the math gets gross and I'm too lazy to go through it. Be my guest, but I'll guarantee that the results will be an almost imperceptible gain over their regular shooting).
So, we begin to see an interesting phenomenon (re: Doom vs. Guide). Choosing what to use Doom on (by determining what will be able to fire on the affected unit) vs. using Guide on one of your own squads is dependant on which roll the unit is more likely to fail. So, Avengers get a bigger boost from Doom because the hit on 3+ but only wound on 4+. Spiders get the bigger boost from Guide because they hit on 3+, and wound on 2+.
These are intuitive results, but only when you stop to really think about the game mechanics behind the numbers.
Now, just for giggles, let's look at what happens when a Striking Scorpion gets into close combat with a Meq that has Doom on it vs no Doom. It's rumored that Doom affects close combat hits as well as shooting, sooooo....
I'm going with 4 attacks here (1 base, 1 extra CCW, 1 mandiblaster, 1 charging), so YMMV as this is a 'best case scenario' kind of scenario.
Scorpion (no Doom): 2 hits, 1 wound, 1/3 dead = 5 pts of dead Meq
Scorpion (Doom): 2 hits, 3/2 wounds, 1/2 dead = 7.5 pts of dead Meq
Interesting correlation to what's shown above for the Avengers, no? It's because Avengers hit on 3+ while the Scorpions only hit on a 4+. Amazing what a single pip can do for one's averages...
Anyway, I think we'll see a major shift in the way that most Eldar lists deal with Meq opponents. Since they can make their shooting so severe, and this same shooting will be absolutely brutal against any non-power armored foe, I think they'll be more dependence on massing huge numbers of wounds and forcing the Meq player to roll bucket loads of saves rather than simply ignoring their armor (alla the Starcannon horde). In effect, the power gained through the new 'dex places a higher importance in combined arms and huge numbers of dice being generated. It's the armies that can take the most advantage of these new mechanics that will end up in the top of the tournament scene because they'll be able to handle all comers through the power of never ending dice bucket.
Comments, critiques, et al?