When reading through the beta I - being an old heretic - noticed two (personally depressing) things:

1. Mutation tables are completely removed in favor or "suitable" Traits. Now, I know the game isn't about sprouting horns and tentacles or going eight-limbed on you best buddy the Commissar, but still the lack of dedicated mutation tables is… disappointing, somehow. Also the Traits offered in the corresponding game section as suitable for mutation choices are nothing like "minor": a Burrower or a Toxic Blood are rather extreme for the first taste of corruption, and will get your character a piece of Emperor's Mercy in no time.

Maybe the tables were excluded in beta version only, for simplicity's sake, but I really hope they'll make it into the final version. Pleeeeeeeeeease?

2. Imperial Psykers - IMHO - are somewhat overrated. Their powers (both in potency and scope) are a bit more than could be expected from an IG sanctioned psyker (often a self-loathing, brainwashed creature despised and feared by his "fellow" soldiers, and constantly under surveillance for the slightest sign of "taint", whether true or perceived). Besides, I didn't find any Sanctioning Side Effects for a psyker, and they were really half the fun playing one.

That said, using Black Crusade pattern Perils of the Warp on IG psykers seem like overkill. I mean, c'mon - a psyker may be a badass, but his companions don't deserve (or stand a chance) fighting a legion or two of daemons each time he drops the ball. Dark Heresy pattern Perils - still life-theatening but not so deadly - would fit in better in this case. Once again, IMHO that is