Rufus Shin-Ra could easily become Fake Rufus Shin-Ra.

I have trouble with the fact that they've basically told us it's him with the "Mr. President" line without actually showing us so. That and the scene with Kadaj kneeling before him, and the fact that, as it stands, there's no known origin for the new Jenovaroth. I'm not saying that Rufus definitely isn't Rufus, but I expect there to be at least one big plot twist in AC, and that would qualify.