I posted that after posting this
and seeing how many new people had posted in the thread without taking most things into consideration.
As he said, the game is CPU limited. I definitely believe him, as Ubisoft's PC games tend to have the same problem. I also believe that they had intended to do more with the game, but had to reel it in once the specs of the new consoles were set. This may have resulted in Ubisoft simply setting a target and deciding that the game looked good enough once they had hit it, but what seems more likely is that they did as much as they could with the time they had (which was likely much less than the developers would have preferred) and that, while they both run at the same resolution, the PS4 version will end up looking better anyway.
Rather than consider the situation rationally, though, the general reaction seems to be "he said parity! Get him!".