I don't see a problem with NPC's being individuals, and players gaining circumstantial advantages for being the kind of person an NPC would like. But this is universal- there's going to be just as many NPC's who value a keen, academic mind as someone who heals the infirm, or can triple the yield of a harvest with magic. I can't see one character gaining this sort of advantage more than anyone else.
But being gregarious and socially dynamic is a trait that is universal, by it's very definition. People are going to be drawn to characters with high Charisma, even if they have made pacts with devils or their great-great grand dad had a fling with a dragoness. That may work against them, but it won't ever nullify their charm, confidence, and poise. They have that je nais se pais, that quality that lets them be popular for...uh...being popular, like certain celebrities I could name.
The fact that the game allows you to be intelligent, wise, or persuasive and lets you convert that trait into combat or exploration effectiveness is a little bit of a problem. Maybe you shouldn't be able to use Dexterity to hit and damage with weapons. Maybe shillelagh shouldn't be a thing.
And definitely, maybe Hexblades should have to give up some casting ability in order to wade into melee combat! After all, if it's not important to have a high stat in Strength to be a Fighter, then it follows that a magical swordsman might not need as much Intelligence or Charisma either!
It's double dipping, and the Fighter should be allowed to do it too! If traits exist that let me swap one ability bonus to another, or even add one to another, then I think my Fighter should be able to use the ability scores he values to other things as well! And if, for some reason, adding more abilities to the Fighter somehow makes them too strong, you can take Indomitable away, I won't mind!
Or even better, delay Action Surge to a higher level- it's too easy for multiclassed characters to get it anyways, if you ask me!