RotJ is basically three movies in one: Han's rescue, the Endor mission, and the Death Star.
Han's rescue is a 5-10 minute 007 opening sequence that includes, for no good reason, about half an hour of setup that does very little for the rest of the movie besides unfreeze Han. The choice to have Jabba's lair be on Tatooine was unfortunate, lazy and entirely avoidable, and the rescue "plan" makes no damn sense.
The Endor mission is a narrative and character-wise dead zone (I'm counting Luke and Leia's chat and Luke and Vader's meeting as being part of the Death Star section, because I can). It's overly cutesy, but also engaging, and the forest is a great new environment that offers hope for the future after the previous movies' planets of sand and ice.
So far, we have a mediocre to bad movie. But the Death Star stuff is genuinely excellent; just as good as
ESB's filmmaking heights. And, after all, it's better to start a movie weak and finish strong than vice versa.
Conclusion:
RotJ is the least of the OT, but still the third-best
SW movie in terms of spirit and heart. (I acknowledge that, taken strictly on its own merits and in isolation,
TFA may be a better
flick, but I really can't forgive what it does to our three heroes post-Battle of Endor.) It could definitely use a fan edit to cut down the non-Death Star stuff to a minimum,
mute helmet-less Anakin, and
delete the Force ghosts at the end to keep the focus on our heroes. (I'd do it myself, but lack HD editing capability.)