SE had this idea already I think and decided to go with what we know now as FFX-2, because having Jecht in spira would be almost the same as the FFX original. Same maps, same enemies, same bosses, same all-important end decision in zanarkand and we already know what happens.

I agree with whoever said about the bevelle-zanarkand war. They touched on it a BIT with FFX-2 and Shuyin but not much. Particularly a detailed story of Shuyin's life would be very interesting (mainly because I haveny played ffx2 in a long time )