I don't really follow classes.

I never use Fran, Vaan, and Balthier anymore (I will later, but not at the moment...).

Basch is my melee person.
Ashe is a mix of melee and magic.
Penelo, having two Mist Charges and the highest original MP, is my magic person.

FFTA is a totally different story. I prefer classes there, although that backup set of skills is always nice, considering laws limit what a character can do sometimes.