I hate the Dark UI. I'm sure others love it.
Please integrate an option to change between the two UI's in the preferences. (preferably before the launch of 6--gotta be not that hard to have two options only).
Staring at that "feature" makes my graphic design training flare up. Traditional typography says that type is easiest read with black on white background. Even worse it looks like gray on black, which is even worse to my typography training.
I'm sure others will love it. Thus a switch.
Besides, there are old people out there...