While I'm the first to admit that I'm not an expert on ROTJ, I do think it looks good. Out of the few improvements I can think of you have already identified most of them. The only thing I don't see mentioned that I think could improve is to get the lower thighs slimmer to avoid the "barrel" look. I'm not sure how easy that is to do with overlap assembly, so I'm leaving the practical implementation to those more experienced with that kind of building.
What is obvious though is that you sure look like a ROTJ trooper, and a good one.