I don't think that a simple button or check box produce a significative complication in the software use but allow you to obtain great improvment about the final result. I don't say that the sunflow rendering engine isn't good, it is really good!!! I know that result and is a very good result. I think that SH is near to obtain a great jump with some very little steps. the smooth, the model rotation, and the possibility change color and/or texture(not the form that is for a modeller) of part of model are the final steps