As for appearance, as I said, any number of things could have happened. It is a somewhat solid argument, but hardly a concrete one like just about everything else that disproves it, like you're number 2.

As for a complete flip, look at how much time has passed. Under the assumption it was true, a lot of skullskullskullskull was bound to happen.

1) Squall dieing, as obviously he wasn't alive in the future, and Rinoa was. (Under the stupid assumtion it was true) so there was the loss of a loved one involved.

2) As directly stated in the game, the discrimination and hate of sorceresses, which Rinoa was. AFter living through all that Ultimecia has, the whole Wars and such, that is definately bound to change a person.

Again, I don't believe R=U, but in the cases of Appearance and Personality, they just seem like weak arguments to use against it, especially considering the other evidence that damns the theory.