Cyberarmy
Love fool
The only way to make Charisma useful in combat is to remove the player's control
Usage of intimidation for cripling enemy morale/strength in Underrail was nice imho. And persuasion can be used for strengthening our party members, to wind them up maybe?
"Warcries" that can be used for area buffing/debuffing sounds good enough for me.
That's already a lot and we don't have the manpower to handle more design 'challenges'.