The next major jump for 3d games (mainly shooters) will be enhancing the physical modeling and getting back to REAL 3d positional audio.
with all the programming in the newer cards you can draw and texture things that dont have to be block/triangles. Someday you will be able to program the materials on the object such as hardness, tensile strength, temperature, etc. Shoot a brick with a pistol it makes a divet, shoot it with a flamethrower it gets hot and glows, shoot it with a rocket and no more brick. Completely deformable enviroment that doesnt look like your walking around in a perfect square environment will work. Be nice that if you cant unlock a wooded door in a dungeon you can burn the thing down. Cant get into the basement level, load c4 onto the floor and blast into it. Real 3d audio where you hear the echo of enemies talking in the next room or walking down the hall (picking off where Aureal left off before creative purchased them) will enhance gameplay along with players talking to each other in the game.
Once these get incorperated into 3d games the others will be old and retro. These changes will alow games to have many possible endings instead of the pre planned way games run today where everything has to be done in the exact order to win (if you forget a step your permanently stuck). Basically you will look at the old 3d games like you look at Myst and the old laservideo games instead of clicking and watching the pre rendered movie your actually in control of whats happens.