I often need to operate the controllers while my 93 yr old mother just "enjoys the show" - for example when watching 3D videos.
The problem is that its almost impossible to operate the HUD controls because the headset wearer is constantly looking around and thus the HUD moves accordingly. The special CAST mode I propose has all the oculus HUD ( and APP HUD ) controls appear ONLY on the CAST screen ( until cast is turned off ) and has all the HUD buttons etc appear fixed in place so that one can operate the buttons easily.
So for example this would allow my mother to put on the headset - then after turning on CAST - I pick up one of the controllers and point and click buttons. And I wouldn't have to keep asking my mother to stop moving her head just so I can operate controls for YouTube or entering / exiting apps.