btw i also noticed that the television device have a huge impact on graphics.
my friend got 2 tvs, one 720p 7 year old one and one made in 2013 1080p.
we played assassins creed 4 both on our devices (he xbone and i got wii u).
I the wii u was connected to the 2013 model and the xbox one to the old tv, ac4 looked better on wii u. So as long as your still using pretty old tvs, i guess the gap is even smaller