That right there was precisely the issue I had with Tidus. The fact that he had to keep reminding us that he was the hero. It wasn't his story, it was Spira's story told through his eyes.

And the fact is, to a certain degree he was along for the ride. True, it was actually his outsider's point of view that set into motion the events that ended the Sin cycle on Spira, but he was still an outsider. Unknowledgeable, unskilled for the most part in the ways of combat, and not terribly intelligent. He was not a hero or adventurer. He didn't even want those things. He was enough of a man to accept those responsibilities when they were thrust upon him. He was the avatar for the player, much like Vaan.

The main thing I like about Vaan is that he's a much more streamlined character than most Final Fantasy heroes. Pretty much all of them have some sort of deeply personal stake in the plot, with lots of twists and turns. Whereas Vaan seems to just be a guy who wants to be a part of something bigger. That's different, and I like it. Neither his mental stability, nor his survival are his motivations for taking part in heroism. He's just tired of sitting on the sidelines waiting for things to change.