Before my Vaan would use a Sword and a Shield. Now I make him use Katanas and I will probably teach him how to use GreatSwords. As for my other characters, Balthier would use Daggers, Fran would use Bows, Penelo would use a Staff, Ashe would use a Sword and Shield, and Basch would use Axes and Hammers.

I have a lot of success with this type of party, especially since my Vaan is overleveled.