I'd also really like it if Detached Displays would actually show the "player bar" UI controls on mouse-over, the same as Display View does. Right now, if you WANT to control a Detached Display right in the video display window, you can't. You MUST use the Standard View or Theater View UI, usually on a separate monitor.
In effect, I'd like Display View and Theater View and Standard View to all be able to be "detached" and shown separately, but be able to interact and control each other (so long as they are set to the same zone).
A perfect example is using MC to run a multimedia "show" (like DJ-ing or running a multimedia presentation with videos for an auditorium or room full of people). It would be great to have MC running on a machine with a local console showing MC in Standard View, but then have the Display detached and sent to a projector (connected to a second video out on the computer), and then a third "audience-facing" HDTV mounted on your "DJ Booth" showing MC in Theater View mode. Another example might be if you were running the entertainment at a "cocktail hour" or "party" function, and you have a few HDTVs mounted around the place, like they do in many cafeterias and sportsbars. Have a local console showing MC in Standard View, and a touchscreen with MC in Theater View, so that people could queue songs/videos themselves.
You can do this with Tremote and separate computers, which sometimes might be appropriate. However, that requires more infrastructure and can be less robust (wireless can go down and connections can be lost, you might have to deal with firewall issues, and other networking related troubles).