The interviews so far all say that they are only about 15% done with tweaking the engine parameters, so they still have 85% to go. YoshiP also said the settings were not set on maximum because he wants to show the game as it would run on a mid-end system (=what most people have).

It is too early to say anything about the graphics/texture quality, we'll have to wait till they show us more material, especially videos.