And in news that surprises no-one, Yoshida is again cagey about when they're going to re-reveal Gravity Rush 2;
http://www.destructoid.com/sony-waiting-for-the-right-time-to-unveil-gravity-rush-2-294502.phtml
At this stage, I think it's a certain thing the game is going to be on PS4. There's no way they've spent 3 years in development (and counting) making a Vita game.
Whether it comes to Vita as well as PS4 is another story. I doubt it, really.