I like Tidus/Yuna pairing, but I could have done without the preordained aspect of their relationship, which no amount of affection ratings can alter. It's like giving Rosa a Cecil/Kain/Edge affection rating and then she picks Cecil every time.

Tidus/Rikku would have been neat, and it looked for a while that they were getting close on board the salvage ship, but then along comes the Deus Ex Machina in the form of Sin.