Asside from Penelo, if any other character were to just disappear from the game, I would miss them. Vaan and Penelo seem like they don't belong.

This is all pretty much just a matter of personal taste. I like my bread with butter, you like yours with jam.

My guess is Vaan's character will develop later, at least I hope so. I don't think either of us are far enough into the game to say.