Tidus isn't always whiny (though he certainly is whenever Jecht pops into his head). He's just annoying and stupid. Almost as stupid as Wakka.

The battle system was decent, though the rock-paper-scissors aspect became mildly tedious on occasion. The sphere grid system was ok. Overall the game had the mechanics to be a good game.

And then it came to the writing. Between his Hope-esque whines about how horrible his father was and his general goofiness, I tended to dislike any cutscene with Tidus involved. I have to agree with Daniel that the best part of Tidus was that he wasn't real (despite that plot point being painful to think about). Yuna was the standard perfect love interest and thoroughly boring for most of the game. Lulu and Rikku were actually interesting, but ruined by blatant fan service.

Additionally, there are two ways to do JRPGs without a traditional worldmap: the FFX/XIII way, and the FFXII way. In FFX, the world -- which otherwise seems richly developed -- feels stunted and small. You get a feel for bits and pieces of it, but nothing to allow you to appreciate its scope. In FFXII, on the other hand -- and regardless of how you feel about the rest of the game -- the world feels massive, and you really experience a full trek across the world.

FFX's plot, overall, was actually pretty good. Though it still doesn't hold a candle to the more well-developed tales of FFVI and FFT.