I think I'd like, quite a bit, for the thing listed on the kickstarter updates FOREVER ago to be in for the undead ; the Soul Eater or whatever, where you rip a soul out of an enemy and they berserk until they die.
Similarly, I think undead should have +2 constitution (Tougher to destroy, since they're dead and have no real vitals).
If they get anything else, I'd say probably some kind of skill bonus, like Dwarves get like maybe Lucky Charm or what have you.