The PS3 and 360 have pushed things pretty far in terms of shallow graphical processing (polygons, pixel effects, etc.): but with massively more processing power (which should be available by the next gen) there's a lot new you could do in terms of physics and AI that's not feisible today. E.g. apply real physics to *everything* in the game world (not just a select small number of things), apply much smarter AI techniques (e.g. recursion, etc.) In terms of control, I don't think stereo cameras would be practical because of the set-up involved, and how carefully you'd have to position yourself. The sensor bar is hassle enough. Voice, while an element of control in some games, I don't think will become central (e.g. it adds an interesting element to things like Manhunt and Brain Age, but I don't know how you'd design a whole game around voice recognition, or if you'd want to)