It would be great, if there was some way for interacting with the game of the current Quest User through the App, when you are outside VR. For instance, I could imagine in Richies Plank Experience to have the option, as an onlooker with the Oculus App that's linked to the quest, to spawn a spider in the persons face, or trigger other events. Similarly, in other games there might be options of triggering new waves of enemies, or speeding up / slowing down a song in BeatSaber. The possibilities here would be endless, and it would allow for a whole new way of interaction between the people who are watching somebody play and the person playing. I think it would make the Quest even more of a social/party device.

I am aware that this is a bit of a big one. It would in the end be up to the actual game developers to implement, but I think it would be a great feature nonetheless. What Oculus should do, is to create the libraries/framework to make that interaction possible through the oculus app itself.