The thing about FeMC's design as she is meant to be an entirely different character from Minato. Just taking a look at her text choices, she pretty much more light-hearted, bubbly and happy. Heck some of the characters in the game describe her as endlessly happy.
Genderswapped MC is really really hot. Would I replace her(him?) with FeMC? No. I really like FeMC as she is, she gives a nice new perspective to Persona 3.
Agreed, FeMC is diffenetly way more outgoing than Minato is. Actually, if we think about how Minato cant even get S.links with the guys in his own dorm, it lends one to think about his canon personality.