I see. This is quite a problem because my entire UI + Aurora is based around 1-pixel borders, offsets, and pixel fonts.
I don't understand why the WoW UI works in such a strange way. In order to get exactly the same UI size on a bigger screen, you need to 'scale down' the UI. Weird.
I'm going to ask Blizz if I can somehow set the scale below .64, I suppose.
Edit: Funnily enough, Tukui works just fine. I need to check out how it handles scaling.