To me, the font titles look horrifically childish, as does the watch button. The old one had an eye which made sense, but the new star is irrelevant. The font on the quote and submit buttons also looks less professional.
There is way too much orange now, it's highlighting things that shouldn't be, like the default avatar and the left/right buttons on the homepage.
I like the new reputation "orbs", but the hands look awful. Opening spoilers looks nice too.
I'm also not a fan of how flat the post headers (where the username and avatar of the poster are) are either, to me there just isn't a distinct break between posts like there used to be.
There definitely seems to be a dumbing-down of the whole design.