I'm imagining that it might end up much like the transition between the Xbox and the 360, where some games were on both and it was 50/50 as to who felt more ripped off. If it does end up being on both the 3 and 4, I imagine the playability on the PS4 might be insanely better, what with the ridiculous increase in RAM. I can't imagine Ubi is going to pass up a PC release, even if they force uPlay on us. Especially since the PS4 and probably the next Xbox are essentially just dedicated PC architectures. uPlay is horrible, but I'd be willing to put up with it to play this game.
Edit: And also, Wii U has definitely been confirmed as a release console, so it's likely all of them.