I mean, I'm not entirely opposed to some translucency and gloss if it doesn't get in the way of legibility. For me early Mac OS X 'Aqua' circa 2003 is the peak of that aesthetic.
Any UI theme should also be applied consistently. What I hated about Vista is the Aero theme was only surface deep. You were always only a few clicks away from some program that look liked it hadn't been updated since Windows 95.