Thief and pirate crossed my mind, but the game puts so much focus on doing good that it would be hypocritical to be a thief.

But if you look at some of the official art for the Maelstrom company, there is a pirate with a gun in it. Possible expansion? http://images.wikia.com/finalfantasy...er_%2B_Art.png

I've always liked Red Mage, as well, but that's always been a self-sufficient kind of class. They have good damage, if I recall correctly, plus white and black magics. They wouldn't fit in with party play very well.