Jenova. Without a doubt and for ultimate justice. Jenova is what I want to be as a person. Only without the being dead and having my head be carried around my my nutjob son.
I'd be Seymour. Solely for the attempt of re-defining his character to be a little more tactful... and less high-pitched. Oh, and I could die and come back multiple times, just to spite the ****ters who think they're better than me.
Zidane for sure. Having a tail would be interesting aswell as living your life stealing **** from Alexandria while making out whith their princess at the same time. Who wouldn't want that?
I'd be in Tidus's position. blitzball seems pretty awesome, and I want to be taken somewhere far away, somewhere new. I literally just want to be taken off my feet and somehow go to some place totally different and in the future.