Come on, ROTJ has everything. You know it to be true.
Best space battle? Check - battle of Endor.
The Luke v Vader lightsaber battle is awesome, so is Vader's redemption (minus the special edition Noooooooo).
Leia in a bikini - awesome.
It also gave us Jabba, another plus.
See, almost (though clearly another who can't get beyond the end of Tatooine with enough blood to their brain rather than elsewhere)...
The issue I have is that Star Wars literally wrote the rules on how to make a Hollywood blockbuster. Empire followed those rules and scaled it up (actually, turned the epicness on its head - Empire is a funny one).
ROTJ ignored them.
Basic rules are:
Action intro
Heroes Journey (hero meets wise man, goes on adventure to rescue somebody).
Peril that the hero overcomes/resolves.
ROTJ doesn't do that. It's a slow start, then it wanders a bit after Tatooine and then there are THREE perils to overcome at the end. There's no focus, but lots of Ewoks.
I think it starts well. Tatooine and Jabba's palace gives us a glimpse for the first time of a much wider universe. It's diverse, clever and works really well. I actually love the start of ROTJ.
Then there's the whole Luke visiting Yoda thing. It's a bit bland and a nothingy middle. Not much happens, no new revelations. Just "meh".
We then hit the "finale" which is a jumbled mess. There's the whole screw up on Endor with the Ewoks. That leads to the three pronged finale.
You have the surface battle on the moon, the death star battle and all this around the seduction of Luke by the Emperor and his final demise (spoilers
).
It flits between each scene, never giving any of them a chance to really shine. Just enjoying Han and Chewie fighting on Endor? Tough, we now have A-Wings against a Super Star Destroyer. Before that concludes..? Luke sulking in the dark.
Etc.
It's too busy. Each bit is individually good, but there's too much going on for you to get into. It destroys the tension.
Compare it to ANH and ESB where the finale centres on one conflict, with just occasional shots to other things to round it out - the focus in each is the Death Star Run and Luke's fight with Vader though. That's where the tension and captivation lie.
Oddly, TPM mirrors ROTJ at the end. It's almost shot for shot the same ****. Instead of Endor you have the attack on the palace. Anakin against the droids. Jedi Battle. All flashed between each and the whole thing as much of a mess. Yet people think ROTJ is awesome and TPM is crap - yet they used the same writing model for both.
I will always support TPM for the Jedi battle with Maul. I think it's one of the best sequences in the whole 8 cinematic episodes so far. It's just constantly ruined (as was Luke's battle and the Battle of Endor) with cuts to other scenes breaking the tension and interest.
But, at least nobody died of a broken heart