Lucas tries very hard to have the moral gray that is so common among other SF franchises but there are some missteps that hang it up, in my opinion.
I disagree. I believe that Lucas is very good at it . . . to the point that I suspect it made a lot of people uncomfortable. It seems as if they're willing to tolerate moral ambiguity in other SF franchises, but not in Star Wars. I've noticed that every time I've pointed out some moral ambiguity in the Original Trilogy, some fans will try to dismiss it or create excuses for the questionable behavior of the main characters.