Here's a few more:
If you select a file in the list and do Alt-Enter or Right-Click -> Tag Info, then info opens in the Action Window.
All the library tools open a separate dialog.
Choosing to Play/Open the Image (Cover Art) shows the cover art in the Playing Now window, in spite of the fact that the AW actually has File Properties/Image... what is the latter for? If you happen to be playing music, would it not be more convenient to show the cover art in the AW?
The icon for "Print" in the Action Window is exactly the same as the icon for Action Window/File Properties/Image. Bug?
It's called the Action Window - yet some of the items it contains are nouns and some are verbs (actions). I can understand Print, Burn CD & Rip. Yet Build Playlist actually takes you to a submenu starting with... Build Playlist and including 3 other options, two of which have to do with editing, not building, playlists. Shouldn't the top level be Manage Playlists? How about File Properties, Camera & Handheld? These are not actions. As far as I can tell, the only action that Camera does is Acquire Images from Camera, so why not call it Get Images from Camera? (And it is not really just cameras - it actually refers to TWAIN devices, including scanners...)
Aren't there other actions that are more common? For example, Library/Import Media is a much more common action, which actually runs IN the Action Window, yet it is not accessible FROM the AW!
If the AW is supposed to be a sort of Action Wizard, how about the most common actions of all - Play Music, Play Video, Show Images?
Why not make the AW aware of the selection? File Properties pops up something relevant to the selection. Print, then Print File List prints, not the selection but the contents of the current window. However, Burn CD completely disregards the selection.
Sometimes in the AW there is a back arrow to return to previous screen, sometimes you have to click on the underlined title (another UI element used *nowhere else* in MC11). Sometimes the underline returns you to the AW home, sometimes it minimizes the panel. Compare difference in behavior between Print and Tag Info...
Choosing Print... from the File Menu, which you'd expect to take you to a standard system Print dialog, instead opens the two sub-options in the AW. No obvious way to change print settings there.
Conceptually, the AW could be something like common tasks sidebar in explorer, that changes according to the content of the selection. The other mission in life for the AW would be to act as a home for time-consuming background processes, like synchronization, or library updates, or audio analysis. However, it should be clear when the AW is acting in one capacity or the other.
I mean, MC11 is complex, but the AW seems willfully confusing...