Kojima has to do PR for the game on all platforms. It's going to be released on the XB1.
While this doesn't mean blowing smoke up people's asses that "we're going to make them the same," he's not going to make any sort of statements that one version is the definitive version and that the other is inferior due to hardware differences.
Realistically, based upon games like CoD, Battlefield, Tomb Raider and Assassin's Creed, it's a safe bet that it will run at higher resolutions on the PS4, so it will look a bit sharper and possibly run at a slightly higher frame rate. How much smoother and sharper will have to wait until the game is closer to release.







