I'm probably not going to say anything you don't already know, but maybe this will help some folks. I have turned my UI opacity down to approximately 25%. In the wild, battle, cites, etc, the graphics are so "busy" that the UI is practically invisible, unless I look up at the sky. This is neat, because I can still use the compass, and it is never intrusive or in my way either. It's almost as if i'm looking at the weather and sun movement to see which direction i'm heading. But in regular play, it's almost imperceptible unless I strain to see it.

That's a neat idea! I'll have to try that out. Thanks!