I know it's true of fifa, they individually scan a number of player specific facial expressions to go with the face scan. i wouldn't prioritize that kind of thing for my mechanism either.
Signature persona quirks like the way you described Gaylord Perry would be welcome but can't think of a player today that would make the cut for that even though stuff like that is cool. I separate my player demeanor topic from the signature or generic animations / celebrations topic though. I think it stems from older games like The Sims where certain calculations would fixate a mood upon the character throughout the game. That's kind of how I see franchise mode too.