When you use the Core Four-- the foundation of the Dungeons & Dragons game-- nary a Charisma user in sight. Even when you toss in the next level of classes, usually considered to be the barbarian, druid, ranger and paladin... you only gain a single Charisma user. Which is why they decided to finally throw Charisma a bone with the remaining classes down in the third tier... so that Charisma can get a little love.
And before anyone tries to disagree... yes, the bard, monk, sorcerer, and warlock are third tier. Sorry. Some of you may love those classes and believe they are heads and shoulders above the others... but they're still third tier. Sorry. It's history. It's the way it is. Nothing can be done. And thus Charisma is fine as it is for the classes.
As far as it being used for all the social skill checks... we need it to be. I mean, are you as a DM going to rely on your players roleplaying ability to determine how well they convince the ancient red dragon to hand over her treasure hoard? Of course not! That's just crazy talk. You don't use roleplaying for adjudication in a roleplaying game, you use dice. Again, that's history. It's the way it is. And thus... with Strength, Dexterity, and Constitution dominating the Combat Pillar, and Intelligence and Wisdom lording over the Exploration Pillar... that gives Charisma the Interaction Pillar. As it should be. So to take that Pillar away from Charisma and give it to another ability throws the balance all off, and you are a horrible, horrible person if you even consider the possibility.
Don't be a horrible person. Be a good person. And a good person lets Charisma have its place in the game.
You horrible person you.