There are plenty areas where gameplay can be improved.
Gameplay wise voice recognition can start to play a bigger role. Adventure games like heavy rain or rpgs like Skyrim where you can actually talk to the npc's instead of selecting from preset responses. Can't find something, simply ask where the blacksmith is from the nearest npc. LA Noire would work a lot better too this way. However I don't expect this until late next gen, probably not until the gen after.
Extra ram and processing power will also allow more complex procedural world generation. Think of a fully 3D version of Spelunky. World and level modification can be used to tailor games to the things you like. The game could mold itself to your needs while observing you playing it. RPGs could use an AI director to keep things interesting. A good GM puts you in peril as much as he can while given you a way out, instead of presenting you with a long grind of easy challenges next to ones you can't possibly beat yet.
Procedural story generation is in it's infancy too. Develop your own story as you go along is the most desired way to play games. A realistic sounding text to speech engine is required for this. Prerecording all possible responses and predetermining all possible outcomes is never going to full fill true sandbox needs.
Mostly I hope next gen will offer more interaction with the environment and npcs besides killing and destroying. I would really like to see more first person adventure games.







