I'd love a Halo game where you're either set as a member of the Covenant, and fight for them. That could be at the battle of Harvest for example, or perhaps somewhere else.
Also, a Halo game based around aerial combat.
Flying Pelicans and Longswords and Broadswords, Starships and whatnot.
And have a Covenant version, where you fly Spirits and Phantoms, and their space-ships and all that.
Off of the Halo route, I'd definitely like something like Regulith's idea.
A 3D open-world Pokemon Game, possibly with voice recognition and to some extent battle tactics (instead of being purely turn based, imagine more like the Anime, where it's real-time and the moves can use and influence the environment for new effects).
