The point of sound desing is to treat it as a music instrument that follows the orchestra.
I see what you did there about pointing missing hums and clashes but thats the point!
A good sound designer knows when to add or remove or tone up/down a sound so the eye of the viewer can focus on an specific aspect/point of a shot.I said harmony before and i meant if you have a new music choice then the sfx should follow with the proper value/rythm etc. or the opposite.
Ben burtt mentioned that he ve made 5-6 different sound mixes for each shot in ROTJ to see how it works best and what is more aproporiate for the movie.
As for the "randomly" comment of mine i was meant to say the clashes and buzzes sounds are placed like random, not the channels ;)
For Feedback and only i just loved the musicless version of this duel. Taking the comment that the music are the sabers and something more than that is over the edge. Awesome example for less is more! :D
Use variation on every aspect you can. Thats Star wars. Nothing sounds the same twice. Thats why i like when im listening random laser sounds from the same guns. Again i recomment the clone wars episode that obi fights grievous on the bridge for reference. The sfx is marvelous!
http://www.youtube.com/watch?v=VwRI07o952I&feature=related
-Angel