We already hit the point of photo realism, and there is more important visual aspects going forward. Such as visual effects, more importantly the amount of it , so the cpu is going to be much more advanced to handle so much on screen. Mesh shading will also be a game changer in this regard. Also as important the amount of object on screen and the draw distance, massive scale with so much on screen calculations.
I'm still waiting for that game where we get invaded by Aliens from space. Where you look up to the skies and you see millions of ufo's descending from the clouds, all highly detailed . Imagine being in awe from seeing things. We are probably a good 10/15 years away from cpu and gpu technologies doing the unimaginable/