Willpower exists in some fuzzy place between Wisdom and Charisma. We don't have it as an attribute though, outside of resisting mental influence, because nobody wants to be told they lose agency over their character because they're don't have the guts to perform an action (and now I'm having PTSD over arguments about bravery in the Halfling thread).
The thing I still can't get over with this discussion is it feels like people want to say individuals have high Charisma "because they're pretty". I don't think that's actually the case.
I think what people want is for there to be some quantifiable advantage for beauty that they can point to, because, as I admitted in my first post in this thread, people do react better to beautiful people. But because standards of beauty might not translate from species to species (Elves notwithstanding), this quickly starts to break down. What a human finds attractive might not hold true for a Warforged or a Tortle or a Bugbear.
Charisma as an ability score rates how, well, "charismatic" you are, withshallow or superficial factors like physical appearance stripped away. "But", some hypothetical person might argue, "wouldn't a pretty person with high Charisma be, you know, more influential?".
And again, maybe. But not necessarily. Hags, for example, are said to hate beauty in all it's forms. So how are they going to react to a beautiful Nymph? Not well!
And of course, as previous brought up in the thread, what about circumstances where the beauty of a person cannot be beheld? Does the Warlock's Charisma drop because they've surrounded themselves with a cloud of darkness? Some might think so, lol, but the Shadow terrifies the stuffing out of crooks when he can't even be seen!
5e sidesteps all of these issues by ignoring physical appearance, leaving it up to the DM to rule on a case by case basis if it should matter. And there are compelling reasons why they shouldn't, given that we have the "unearthly beauty that affects many races" of the Elves right in the PHB. You'd have to rebalance all the races and monsters with a "hotness factor" that modifies their Charisma positively or negatively.
I mean think of how many monsters there have been over the decades that are described as "a beautiful woman, but..." where they could be half animal, or demonic, or what have you.
And then you get to the part where you're dictating to a player what their character should find attractive, which is a huge morass of "nope".
You want to say your character is charismatic and hot, go right ahead, nobody is going to stop you. But saying your character is charismatic because of their hotness is always going to bring up these debates because it's a complex issue.
People always used to tell me how overwhelmingly hot Angelina Jolie was. And I just didn't see it. "She's ok, I guess", I'd say. And that's not getting into how many celebrities are considered attractive who have the personalities of wet cardboard.
To repeat another poster, Charisma is Objective, Appearance is Subjective.