To be brief, after playing a few quick games and reading the rules over and over, I arrived these conclusions (among others):

- It makes little sense to cover resistance to psychic attacks with the Evasion skill. A good swordsman who parries blows with ease is hardly expected to ward himself against Warp attacks.

- Currently, there are many circumstances in which a player will be called to test Toughness to resist poisons, toxins, pain, drugs, etc. instead of testing on a skill. In DH1, I used to houserule the mandate of the Carouse skill, transforming it in a general resistance skill.

A Fortitude skill would include both these concepts. Fortitude (T) would be used against diseases, poisons, etc. while Fortitude (W) would effectively function as a Deny the Witch.

This is a decent idea, although I kind of feel that resisting poisons makes a lot of sense as a straight characteristic test. Skill isn't really a factor there.

In line with this, I would let the Decadence Talent return.

Accourding to the profiles of NPCs in the beta, Nurgle could be quite present in the sector.

So, Poison, disease & also maybe drugs could be indeed common...

I don't think this is a good idea. Carouse was a dumb skill in DH1 and they sensibly changed it to a straight characteristic test in later games. As for psychic powers, the test to evade the effects are either baked into the power (opposed characteristic tests) or the attack is some sort of mind-projectile being thrown at the target, in which case Evade makes perfect sense. If something falls in between, Evade(WP) might be the way to go.

Actually, Evade (WP) is what you use even if a mind-projectile is used.

Also, the way Evade (WP) is phrased makes it unclear if it is only versus "psychic bolt" kind of attacks, or whether it works against ALL psychic attacks.