MechaTarrasque
Hero
Doesn't that risk overcooking Wisdom, thus simply moving the issue from one stat to another?
If Charisma is too powerful (open to debate on this) and Intelligence is too weak (yeah, I can see this one), the simple solution would be to find some thing(s) that would make sense to move from Cha to Int. One that leaps to mind is that not all persuasion necessarily comes from Charisma - one of Bluff or Diplomacy, for example, could easily be refluffed (rebluffed?) to go under Intelligence based on how erudite and well-spoken you are. And as someone else noted, moving one of Warlock or Sorcerer to being an Int-based class would also be easy.
Lan-"meanwhile, in 1e I'm trying to find things to move into Charisma to make it more relevant"-efan
That is a good point, but I think ranger is the most logic int caster who isn't an int caster (all that time studying prey, figuring out traps and weaknesses), so if we moved the ranger into int casters, then that would open up a spot in wisdom for sorcerer. If we buy into "psionics aren't magic", then we end up with (more or less) 3 of each caster types per mental stat.