Here's the deal. Lighting is The single most important aspect in cg. Hence why sometimes a few spheres can look better than a bryce generated wilderness. Believe it or not everything you see irl is just light reflecting off of an object. Hence when you turn the lights off... Where does it all go? It's still there right? Just like the 3d models are without lighting... HDRI requires more work than allowing bryce to render a default sky as a reflection map. Do you want us to build entire scenes behind the objects? If so, you are insane, the poly count would destroy render times. There is more to rendering than just making it as unbelievably complex as possible. I enjoy provoking realism through bryce, I think it is a "challenge" as it is pretty much the only software I can afford. Sure if I had a couple grand to smack down on lw maya or 3dsm I would, but as the old saying goes, if bryce gives you lemons...Make lemonade.