I disagree, I find that Return of the Jedi is often undervalued. There's a lot of subtlety that's overlooked because of the Ewok teeth-gnashing (most people tend not to pay attention to the fact that they were GETTING THEIR tulips KICKED until Luke started fighting back). The confrontation between Luke, Vader and the Emperor may be the high point of the entire Trilogy, and while it may not have had the most iconic pieces of music, Jedi probably had the best overall score of the franchise (I mean seriously, you have
THIS piece).
Jedi was by no means perfect and had its flaws, but because it's not the original film and it had to follow-up on one of the greatest movies of all time, it just doesn't get viewed fairly.