Warhammer 40K Tabletop XVI: "Terminator? I hardly know 'er!"

[Hootman]

actually, zoans might do better at that again: can vehicles deny the witch? if not, psychic hoods won't help and the powers will go off on normal psychic tests.

While they are somewhat better, they still have the same fundamental problem that they had before.

Zoanthropes: Psychic test, Deny the Witch, Hit, Wound, Save/Damage Chart.
Hive Guard: Hit, Wound, Save/Damage Chart.

There are way more places where things can do wrong.

All units are capable of Denying the Witch (and since the FAQ doesn't cover it, it's POSSIBLE that Grey Knight vehicles get a better chance), and the Zoanthrope only gets one shot against a vehicle even if everything goes as planned. The Hive Guard get two from longer range, ignoring most Cover (and not being effected by Deny the Witch), at the same BS, on a much tougher body, for a slightly lower cost.

While I grant that DTW is generally unreliable (last weekend I played a 3000 point game, had to DTW about once per turn, and rolled a 1 for every single one of them), when there's a psyker around things start to get dicey (5+ DTW). If they're an Eldar Farseer, GK Librarian, or Special Character psyker, things get even worse, because those are quite often Mastery Level 2+ (4+ DTW).