ROTJ is a decent film. But it largely coasts on just how much awesome material was created for ESB. I think George was right to want a happy ending, I don't think Han dying or anything like that would have added anything to the film.

That said it's kind of a lame conclusion with lots of plotholes.

And I'd certainly more than like to see a sort of alternate universe take where the empire doesn't go down so pathetically easily. I like the dark, desparate struggle shown in ESB, but you can go too far. There needs to be light at the end of the tunnel too. And I guess in that sense ROTJ delivers.

In terms of quality, I'd say it's a pretty linear decline. ROTJ being slightly worse than ESB, TPM worse than ROTJ, AOTC worse than etc.