You know some childish expectation ... Like real-time rendering of Metaballs (which is possible but very expensive in a scene ^^;;, Volumetric effects, really huge scenes and a lot of eye candy effects

Some of them are implementable in the engine but ... Is it really necessary ?

At a time I remember I wanted also to integrate Radiosity in my renderer (with precalculation of lightmaps after loading ...) ... But in the end this is really no use . Simple PPL is way more sufficient and harder enough to integrate to a well designed scene