I'll admit that I'm dangerously close to the fence on the new 'official' releases, but I haven't caved yet. I will also admit that Empire has always been my favourite SW movie and ROTJ the least favourite. I used to think that I was disappointed because I had read the novelisation before seeing the film, but later came to the conclusion that it was the story arc (or lack thereof) of the film that led me to like it less.
Think about it; Luke is dressing all in black and has constructed his own lightsaber, which would lead us to believe that he is in a fragile state and could fall to the dark side at any time (Yoda said as much @ the end of Empire), but there's no payoff: he remains a goody-two-shoes to the bitter end. If there had been ANY indication of this in the rest of the film, the big lightsaber battle @ the end of ROTJ would have been more rewarding, since Luke would not only have saved his father, but himself as well. As it stands, we pretty much know that Luke will triumph, so his 'victory' over the dark side is hollow.
This is just one aspect. I must concur with Jay's comments as to the flatness of Han and Leia in this film, not to mention the rest of the characters. I think Kevin Smith said it best when he referred to ROTJ in Clerks as "just bunch of f$%kin' Muppets."