I'd love some procedurally generated content, something like the generated maps in old dungeon crawlers like Rogue, NetHack or Mines of Moria. You could visit ech floor and it would be different evey time, even retracing your steps going back to a floor, it would be different.

On the flipside, every time something like this gets suggested, someone always posts how it would be too hard to balance. Personally I don't see that, the treasue obtainable scales with dificulty, there will be some party combinations that won't work with somelevels, and occaisionally some partywill absolutely nail it, complete a difficult section and get a great reward, but that's all RNG. Unfortunately, people will complain when that happens, cry about balance and in response the content will be nerfed and neutered...much like Exploratory Missions...