Main ideas I would be interested in seeing would be;
-A good werewolves/vampires RPG. Vampire:Bloodlines was good, I think of myself in the minority in liking it, but it was outrageously buggy and painfully broken in so many ways. A Vampires Bloodlines done with a Mass Effect 2/Bioware level of presentation and polish would be awesome.
-A RPG set in an almost War of the Worlds situations, the earth is under attack from hostile aliens. I am not suggesting War of the Worlds, but it could lead to an interesting world and landscape to explore. It would mix stalker/Fallout 3 style living on the land, trying to salvage what you can from houses/cars/whatever, but not to the extent of those games, at least not all the times.
Certain parts of the landscape might be desolate to Fallout3 standards, while others might be relatively untouched, verdant landscapes. Could lead to situations where you KNOW you are outgunned (I mean fuck me, what are you going to do against the walker things in War of the Worlds? They vaporise people), and so it would be interesting. Seeing hulking mechanical monsters on the horizon, the silhouette of a burning city, knowing you can risk it and try to salvage anything in the city, or help people, or just pass on by.
-If anyone has watched the movie "The Road", I envision an RPG like that would be awesome. Very similar to Fallout 3 in a lot of ways, obviously, but I think the over-arching idea of "Reach the coast" would be a great idea. You know where you are heading, but you are working with vague knowledge of where you are heading. A survival RPG, in that you are avoiding raiders/cannibals/whatever, more so than Fallout3, heading towards an objective at your own pace.
The one thing I look forward to is as technology develops, the games brought out are going to become more and more impressive.