I read about halfway through the thread... into the "leadership" discussion... and I thought I'd just throw in my two cents.

Tidus was not a leader to the group. Argue that if you will, but it doesn't change the fact. He was nowhere near as important to the group/to saving the world as say... Squall (I use Squall because ffviii and ffx are the only ff's I've played recently). However, THAT DOESN'T MATTER. The story was about him. It was about how HE got swept up into a foreign world, and how he and the friends he met eventually saved it. Does anyone remember the scene where Auron and Tidus get sucked into Sin at the beginning, in Zanarkand? I remember Auron saying something like, "This is it. This is your story." It's clear that Tidus was never meant to be a leader, he was just the central character of the story we saw. If we saw the game primarily through another characters eyes (Wakka, for example), things would seem alot different, but that would not make Wakka a leader. We saw the game from Tidus' POV because his story happened to be the most interesting (though Auron's might have been pretty cool too :P), and not because he was the leader.