Gravity Rush 2 is all but confirmed at this point for PS4. Between a bunch of Vita-only titles going to PS4 and the recent "misunderstanding" of what platforms AskPlayStation said Gravity Rush 2 would be on, where they basically implied it's on more than one, I don't think it's a risky bet that Gravity Rush 2 is one of the games they saw and it's the one from Japan Studio. I'm more curious about the other studio they went to.
If you hadn't noticed, this is Forum 2.0