Threads like this seem to inevitably take a personal turn.
I'll merely make the observation that every aspect of a user interface carries a cognitive load, and each increment (however small) accumulates. The goal of good UI design is to make that load as small as possible.
Things like color and design are not merely a matter aesthetics. They inherently impact usability. The dark look may be simply be harder - and less comfortable - for some people to process.
As does all the damned clicking to load plugins. Having used 6.5 earlier today, I was reminded how much more comfortable I find the fly-out menus.