This is probably the first time that I paid very close attention to the story, even re-loading and re-reading some parts especially near the end. I don't mean to take away from FF7:AC, but FF8 would be able to have a sequel that is consistent with the storyline of the game. No doubt it wouldn't have your typical Hollywood happy-ending, it would be quite tragic. The general consensus about Ultimecia being the future Rinoa, and from the stuff that Squall says after she becomes a sorceress, would suggest that Griever is the future Squall. The transformation of Rinoa into Ultimecia would suggest that something severely traumatic happened to her and/or Squall and caused her to want to destroy everybody and everything. What exactly happens between the end of the game and Ultimecia could start another endless debate, about how Squall could have ended up as a Guardian Force to Rinoa, instead of a simple "Sorceress' Knight". If that isn't movie-material in itself, maybe someone can enlighten me as to what WOULD be.

For example, it could be something related to the events surrounding Julia Heartilly's "car accident," in which Rinoa finds out that her father (General Caraway) has Julia's blood on his hands after doing or not doing something that could've prevented her death. Then he (or at least Galbadia) attempts to 'silence' them and Squall gets killed protecting Rinoa, causing her to become so depressed and bitter that she takes on characteristics of Ultimecia. Dr. Odine's "Junction Machine Ellone"
eventually gets completed, and Rinoa kills Dr. Odine and takes it for hers and goes on her rampage to destroy everyone, everything and every bit of evidence that it ever existed (good ol' time compression). Sort of the same way young-Squall was traumatized by Ellone being taken away so suddenly, and he got so absorbed in taking care of himself that he ended up being the introvert that he was when the game's story began.

Anyways, just felt like sharing my thoughts. Thanks for reading them!