On the input side of things, we've already had speech input apps like Siri and Cortana that 'accompany' the OS install, so what about baking in at least some of the kind of 3D functionality of a user friendly game engine (e.g., Dreams) into the OS UI or even broadcast functionality (like StreamYard or ReStream). Raises the old question: what does baking in additional OS functionality buy you? (recalling that cynicism about this question confronted the introduction of the GUI)