I just wanna chime in with another "So what?". "Science Fiction" and "Fantasy" aren't exclusive from eachother and besides that, as stand alone genres they are very similar. More than a couple Final Fantasy games have already been "Science Fiction Fantasy".
That being said, Fantasy can be boring and generic. That being said, Science Fiction can be boring and generic. Regarding XIII, I don't think we've seen enough yet to really tell how the setting's going to end up being. Obviouslly it's heavily leaning on the Science Fiction end of things and it that's not your preference that is too bad, but don't act like this is terriblly unusual or even very different.
Oh. IX's setting was my favorite.