The differences in res this-gen are much bigger than they were last gen. 720p/792p/900p vs mostly 1080p with a couple of 900p titles on PS4 is a wider gap than anything that was on last-gen, I believe. We also have much bigger framerate differences than we had last-gen (BF4, Tomb Raider, Sniper Elite immediately come to mind), and some X1 multiplats are missing effects like AO, have worse shadows and have more screen tearing.
I don't know how you can say it's not as bad as it was last-gen. The differences have been much more prominent this-gen, so far.