Aeneus, you're presuming that the end goal is photorealism. But I think there is a large hobbyist market that would be thrilled with light settings that consistently delivered reasonably natural results with minimal user intervention. Going back to the early days of Lightwave on the Video Toaster, I think that that was one of the secrets of its success. Default settings gave a result that was superior to anything else on the market at the time. For several years, you could pick out a Lightwave scene just by the look of its lighting.