One thing I don't understand is the move to monochrome icons. I'm really bloody good at recognizing shape+color combinations; the old icons were ugly, but I was able to find the tool I wanted in an instant. After the redesign of the icon pack, I always find myself slowly iterating through every icon in the toolbox to try to find the particular abstract monochrome shape I want.
I think a redesign of the icons was necessary, because the old ones don't look amazing. But you can make tasteful icons which are also colorful and recognizable.
(And I know you can switch icon themes, but when we're talking about UX, we're largely talking about the out-of-the-box experience. 99.9% of users are going to stick with the default icon pack.)