I am prototyping a game right now via .Net and xaml (its a metro / WinRT app). The game is very ui intensive. It requires floating windows, item lists and a bunch of other things the .Net Xaml UI is great for. The actual 'game camera view' right now is of course limited to a rudimentary sprites on canvas.
After my alpha, I will need replace my 'game camera view' with something else. It would be great if I could import my Unity3d application as a .net control, expose an interface to which the two can send messages, and in effect use both.
This feature already exists for html (the web plugin). Why not make a .Net plugin control?