What you call his obssesion with symmetry is something he has explained that in operas you have repeating themes, and he seems to be fond of the idea, which by the way is not specific to Star Wars, Back to The Future also uses this license to point out that history tends to repeat itself, something you can see also in the Terminator Movies (pictures of which I see in your signature).
IMHO I find it interesting to see the repeating themes and parallelisms....