Does it improve the framerate more than setting Wii-U output to 1080i (which helps a lot but looks worse)? And is the cost of this a lower dynamic resolution, decreased draw distance (I noticed a lot of pop ups, but it was a new village which I never visited in the 100 hours before, so I cannot compare) and even more foggy smog?
If you improve the framerate, it must come at a cost unless you rewrite the flawed logic of badly written performance eating shaders. I did not play for two weeks so it is hard to compare.