Yes, the first thing would be the originality. Let's people CREATE new stuff, not only do copy-paste games. And don't say "All ideas have already been done", this is bullshit. Just look at the freeware scene and you will see that.
Games that require skill instead of large amounts of time to be finished. 3D and 2D could live togeter, just imagine what could be done in 2D with today systems.