I'm pretty sure Tidus isn't all that well rated in the first place, let alone overrated :P

I would say General Leo. He's cool and all, but he doesn't really do much for the story, and he may be one of the only nice guys employed by the empire, most of his love comes from speculation about his personality and ambition rather than what's legitimately fleshed out. He's in a total of like 3 scenes and people act like they know all about his character and how awesome he is. I have no problem with him. He just doesn't mean a lot to me. But maybe it's been too long since I've played the game