Assuming it's the GPU holding the X1 version back (I can't think what else it would be), they should probably have released it at 720p. The frame-rate on both is disappointing (if expected), but the X1's is pushing the line a bit too far, even for a demo.
I'm not expecting either version to hit 1080/30fps, but they still have plenty of time to refine both the core engine and game. I'd be surprised if the final version wasn't at least a degree more stable.
Regardless, FF15 is looking great. After so my years of the PS3 and 360 (and the WiiU's rather lacklustre introduction to 8th gen tech), it's nice to finally see console games with complex lighting, animation and shading systems. All often do far more to bring life to a game's visuals than simply bumping the texture resolution or adding slightly more complex geometry (which has been the sort of upgrades we've seen from many cross-gen games...).
