Well, Word Bearers fluff says that mutation is rare, though they almost revere the one directly touched by the Dark Gods...I hadn't considered making Possessed Troops.
I am wary to put an 'arms race' in by trying to have X USRs each or whatever...I seriously thought about Tank Hunters, and in the end felt it too much - they are about Sieges, not tank-hunting. Plus, it detracts from Chosen paying points for it, which I plan to reinstate.
IW making Devs (Havocs!) Troops would be more than enough without cheaper too, lol. It would be good, no question, but I'd need a way to make them only an option, not an auto-pick. The last thing I want if for them to become the obviously best build (again) and play like it was 4e all over again.
One thing I should have stated was part of my Design Brief was that I don't want Chaos able to do Melta like Imperials.
Of course, they will get fairly easy access, and it IS the only reliable tank-killing rather than suppression - BUT, I want Chaos to be more geared towards MEQ killing, and therefore Plasma-spam. I just have to balance that so they don't auto-win against Nids.
I don't imagine Alpha Legion Snipers, more Saboteurs (and not like in the awful game!)
Stealth may not be overpowered to add, but it makes the Cult expensive.
When I get to it, I will see I think.
Thanks, and keep the ideas going!