Well, I'm a traditionalist and I like having Charisma be a partial measure of attractiveness. I like having one of the 6 ability scores immediately giving me a partial mental picture of what the character looks like. Again, I'm not into writing a 2-page background story for every (or any) character -- I like brevity, and having an ability score tell me about appearance is perfect!
From OD&D: "Charisma is a combination of appearance, personality, and so forth." Note that the appearance aspect is actually the first and foremost item historically mentioned in defining D&D's Charisma stat. The fact that it's slipped away over time doesn't change what the initial design goal was: and the in-game benefit was specifically the very important reaction and loyalty rolls in the game.
If it were up to me, my main grief with modern Charisma is that, indeed, it doesn't make sense to use as a spellcasting statistic for Sorcerers. It's an obvious shoehorn to make up "something" that uses Charisma for the prime requisite. I'd prefer to fix Sorcerers is this regard and not re-define Charisma for them.
Note that even in AD&D Charisma and Comeliness were definitely still "linked" through a significant bonus to the roll -- the intention was to explicate exactly how much of your Charisma was due to Comeliness.