I've been reading this thread from afar and now I'd like to voice my criticism as well. Why I hate iTunes 11:
No way to open playlists in separate windows.
I have to flip between playlists to compare them now.
No way to jump to Songs view from any other view as you were previously able to do when you inverted the Store link in iTunes 10.
Songs view is easily the most detailed view. Before you could invert the iTunes store links to jump to that song in Songs/List view and your column browser will be set accordingly. Very handy for me and I used it a lot. Now you can only jump to a song in either Album or Artist view. Neither of which can be customized to show the same level of detail as list view. The only workaround I found so far was jumping to either view, highlighting a song, and then switching to Songs view. The song you highlighted will be on top, but your column browser still won't be set so you won't be able to, for example, see the playcounts for only that artist's songs without manually setting it yourself.
No way to keep repeat and shuffle settings for different playlists.
Before if you had one playlist that you always shuffled and/or repeated it would remain that way until you changed it. Now all lists share the same setting so I must remember to always set the shuffle and repeat to what I like whenever playing a list.
...and of course as the TC along with countless others have mentioned:
No way to preview album art from any given single track.
This is just lame. The album art you see when you switch to Album or Artist view is not necessarily indicative of the album art placed on that track. To get that information, I must now select a track, Command-I, and click on the Artwork tab.
No album art in Songs/List view.
And this is even worse. No workaround here.
As you can see, for me iTunes 11 is more about what you can no longer do than what you can. I am only glad that I stopped using iTunes as my primary ID3 editor years ago less I run into the same problems others have.
My replacement software of choice right now is iTunes 10.7, but since I have an iPad-mini, I need 11. I have voiced my complaints to their feedback system and will continue to do so until something is done or I resolve the issue in other ways. In the meantime, I will research other software to see which ones I can easily export years of iTunes metadata (playcounts, last played, date added, etc.) to. It's a real shame that it might come down to that as I truly loved iTunes pre ver.11, but if it doesn't work then it's time for me to move on.