I also can't live without column browser. Almost every day I need to sort by something other than artist or album. In the past month, I've sorted by composer, plays, last played, comments, disc, track, and date added. Having to switch views to sort is stupid.
I don't use the artwork at the bottom of the side bar to add art to a track, but I do use it to see if the selected track has the correct artwork. Get Info doesn't work for me for that. It's much easier to see subtle changes in artwork when it changes in the side bar.
Another idiotic feature is that Show in Playlist is only available when the sidebar is closed. That makes no sense at all to me. It went from two clicks in the same area of the screen to four clicks in different areas of the screen. I would love to know the reasoning behind this because it required more work on the coder's part to do this than to always have Show in Playlist in the context menu.
Making the look and feel closer to the iOS music app is not something I like. I dislike the iOS app so much that after playing with it for a week, I decided my iPhone wasn't workable as a music player.
A year ago, I bought a Mac Mini to use just as a music player. I'm now regretting this because I foresee a time when I'll be forced to either upgrade to iTunes 11, which I don't see doing, or switching to a Windows based music mananger like JRiver or Media Monkey. I have no reason to own a Mac other than for playing music since I use quite a few apps that only run on Windows. The direction iTunes is going means I'll probably never buy another Mac.
I see iTunes 11 to be Apple's equivelent of Windows 8 Metro interface. Dumbed down and something only fan boys or non power users can love.