If you watch the movie with commentary from the Japanese producers, near the end during the crater scene, they'll talk about a huge summon battle with Ramuh and a few others between each planet's lifestream. Both were going to summon up huge monsters and have a huge battle.

The only thing that kept them from doing this was because the released scene had already taken up so much memory that it wasn't really possible to do the huge battle scene. So now with all of the technological advances happening, don't you think that if they added that scene, plus editing it to make it more Final Fantasy-like, it would actually make it an awsome movie? I sure think so.