Well photorealism, im a perfectionist and easily find myself tweaking 16 hrs a single material for grass whilst collecting 60 reference pictures from a specific species (example: lolium multiflorum, agrostis capillaris, etc) and even modeling it in medium/high poly with realistic folding/rolling for scattering use (yea ik it will be slow but quality > quantity, but were all german here so i think we understand that concept very well haha). I was mostly using Arnold but wasnt really satisfied, spectral renders are just the best in my opinion. But to the actual question, realistic archaeological reconstruction in a way that it can be imagined like modern cities/houses/things on pictures. 
and thanks for the recommendations!
