Small advice, don't judge a console's performance or a game engine's performance , by the resolution it's running at on console.
Resolution is very easy to change at any time without breaking the game, and is among the few visual/graphical options that affect performance evenly, regardles of the current load. There have been 2-3 games since launch of this generation of consoles, that have had resolution's raised by a day-one patch. This is precisely, because they couldn't hit performance targets and decided to lower the games res, to keep performance at a reasonable level. While the game went gold (physical discs were being made) they were working on a day-one patch, to raise performance and thus the resolution.
My point is, droping resolution is often the easy way out, and it's not an aqurate measurement of performance. Of neither hardware nor software. Altough there have been murmurs that for Xbox one, small size of the ESRAM is causing problems at high res. I spesificaly remember this as the explanation from Crytek, behind Ryse being 900p and using a post process AA solution instead of MSAA.