First of all I’d like to give myself a pat on the back; My last two suggestions made it into the game one way or another.
Piggybacking on that I’d like to maybe suggest adding rare but positive status effects. For instance characters that have been injured several times but hasn’t ever been “killed” might get a trait such as “hard to kill” giving them hitpoints or a resistance to injury (I know its redundant because that perk already exists) just food for thought.
other things that could be fun are: some characters could be less mentally stable then others (Wild man) so instead of routing when moral is low they just go berserk. You would lose control of them and they would get a very significant stat boost and disregard any injuries debuffs; the catch is they fight to the death and attack everything around them friend or foe. Obviously there would be a priority to attack enemies but a chance that they will attack allies that are adjacent to them, they are going berserk after all :)