It's interesting that, superficially, Tidus more closely resembles Zidane. Both are smiley, energetic types. Yet Tidus has much more in common with Squall as they're both very introspective. Well, I guess it's more like retrospective in Tidus' case but it really does amount to the same thing as far as storytelling goes.

Tidus was a whiny, obnoxious piece of work to be sure but he's also a spoiled sports star who has his first real fight a day or two before he starts off on his world-saving journey. It be a bit strange if he wasn't a bit off.
That's not even counting the massive chip on his shoulder due to both his parents being rather terrible.

Bad parents is something people can relate to or at least understand. Being from another planet is a bit harder to wrap our heads around and empathize with.