Nomura said that the possibility of KH3 on PC is quite possible due to DX11.
All gaming PCs destroy next gen consoles pretty easily. There is really no comparison to the next gen consoles and gaming PCs of today. No contest.
The only reason there is not an emulator is not because a gaming PC can't handle the graphics. Trust me they very easily can. The way the PS3 CPU processes data is in a way very different from a PC. The architectures are so different is why. The PS4 and X1 are very similar which is why an emulator for those will be out before PS3.