Vaan is whiny? He kinda exploded at Basch, yeah, but he got over that pretty quick. That's probably the only instance I can think of. You don't even have to see the story from his point of view. Once Balthier and Fran join the party permanently it's not about him anymore. He's about as immature as any other 17 year old, sure, but he's a pretty laid back guy.