For any person with a healthy love for cinema, hearing the director of one of your favorite movies explain how he did makes the movie even more entertaining and lets you gain appreciation for what he did.
Since the people who download your fanedit are usually people who care about movies, I too think that a commentary would be very very much appreciated!!
And Kershner was indeed a genius. It's a shame that the other movies he made (except for Empire) don't seem to reflect this. (Poor material to work with, perhaps?) Or did I just miss out on other masterpieces the guy fathered?