Ya have to say Evilpaul that sounds like you're drinking a bit too much hatorade or worrying too much about catching the gay.
2 things you have to understand firstly that that a lot of Japanese teens dress what we refer to at the very least as meterosexual and at most dressing like a flamer. Secondly though look at the source material and setting Vaan is obviously a copy of Disney's Aladdin and the setting is in a desert/tropical environment. He's even got similar motivation. I don't remember Aladdin being blatantly painted as a fag despite the fact he was dressed in almost the same way.
Either way if you're thinking he's gay then you're reading too much into things that aren't in anyway there. Seriously he definitely seemed more interested in Penelo and Ashe over Bosch to me. Like maybe he'd go for Balthier but c'mon that guy's like Brad Pitt anyone would be a bit gay for him. Would it have made you feel better if he was busy trying to feel up Penelo or Ashe the whole time?
I'll admit Vaan's voice actor was pretty annoying but at the same time his motivation and story wasn't terrible. Definitely one of the least interesting characters though but not really that bad.