Furthermore, there would be no need for the onscreen "Player Controls" as those functions can be provided by the Android Remote Plugin...
Not everyone uses the Android remote plugin. I use theatre mode mainly to show a second screen while I'm using the laptop for other things. The onscreen controls are very useful to me because it means I don't need to close the window I'm working on to use them (nor pick up my phone and open an app).
I like this TM, but I'd like to see a volume control added to it.