What do you mean by high end? Paragon was 2016...and that was one of the best looking games with a plethora of new tech...distance matching, material layering, stride warping, orientation warping, etc all at 60fps...no other engine was doing that. Shit Paragon is still a great looking game.
I have no idea what was going on in paragon, I haven't played it.
To clarify, by high end in the post you quote I'm referring to my overall general impressions of visual quality and performance on display for specific games.
My choice of 2015 was not an accident, as 2016 is I feel where we got Gears 4 which could stand tall among the top 5 or so best looking games that year. Although most probably wouldn't rank it as
the best looking or performing, since that was the same year as Uncharted 4, Doom 2016, Battlefield 1, and Quantum Break, all of which I think can make a strong case for one or the other (either most visually impressive or most visually impressive for how well it performs).
In 2015, it's an interesting case because the one game that
does look stunning on Unreal is running on UE3, in what was described as a "heavily customized" version of that engine. I don't really know the exact specifics, but in the 2013-2015 period I can't think of any other major UE games that looked abnormally good for their time other than Arkham Knight. That period in my mind is dominated by Frostbite (Battlefront was a stunning game, but the earlier stuff looked great too), Cryengine (Ryse), Guerilla's engine (KZ:SF and Until Dawn), Naughty Dog's engine (TLOU in 2013), and so on.