Hmm...well I guess I wouldn't necessarily want them to be the next big thing that everyone does, but I would like to see a rise of several things.
-Tactical shooters: Anyone remember Rogue Spear? The thing where you got pinned down and hoped you could avoid getting shot because there was no regenerating health or health packs, and if you tried to bust into a room of hostages and timed it wrong with your team half the hostages and your squad died? Then those talented weapons experts could not be used again for the entire campaign due to, y'know, being dead and all.
-Good stealth games: We've had some good ones in the past, so I don't see why we don't have any recent stealth games. AC does not count. Deus Ex let you play stealth pretty well, but that's the only one in years I can think of. Splinter Cell turned into an action game unfortunately.
-Survival Horror: Again, just something I'd like to see more of. Not many can actually make me jump at anything in the game, and so many give you a weapon. Putting a gun in my hand does not make me feel scared. With severely restricted ammo it's doable at least. Maybe a feature where with a pistol I have to have magazines loaded ahead of time, and you can only carry a certain number of magazines. Even with ammo, if you don't have any loaded magazines you're screwed. Better time your reloads well!
-Mount and Blade type game: I like Mount and Blade, but there's still more that can be done with it. Unrealistic to hope for I know, but things I'd love to see are improved combat, vastly improved kingdom and political system, better character interactions, better siege battles, the capability of commanders dying and new ones coming in, the king dying and a new one claiming the throne (even several claiming, possibly splitting a faction into civil war), commanders improving instead of being static, A.I. that won't run in circles around a besieged castle and not freaking help me defend it, actually better A.I. in general, and more but I've gone on long enough.
I'm sure I'll think of more things I'd like to see later.