Why is Bartz the leader?

[Wolf Kanno]

Same reason Vaan is, I suppose.

Oh, cause people are stupid, I get it.

Also having him as the character who travels around helps. I think you can switch who it is that walks around towns and the world map. Although I'm not sure. It's nice to have him as leader cause while other characters has their role, Bartz looks after everyone and makes the hard decisions. I'm sure if someone else was leader we would have a topic asking why the someone else is leader. :P

Not really, cause as I pointed out, pretty much everyone, but Bartz has more experience being a leader than he did. Faris alone is far more qualified than most of the cast.