When I was a teenager, my father lived in a downtown appartment tower with a cinema in the basement. Due to his press credentials he had an unlimited free movie pass. Star Wars played there for over a year, and when we would visit him, if we were ever sitting around wondering what to do, somebody would suggest, "Why don't we go downstairs and see Star Wars?" Today everybody does this but then the VCR was just dawning, so this was something really cool.
So of course that movie held a special place in my heart, and it was indeed groundbreaking, particularly in effects, grand story and perhaps most of all, good editing. "The circle is now complete" as Lord Vader would say.
So I'll repeat what everybody else has said, Revenge of the Sith is far better than episodes 1 and 2 of the modern trilogy, better perhaps than the Ewok-burdened Return of the Jedi. It's an astounding triumph of visuals as well, with a much more moving and interesting story. Yes, the acting is sub par, the dialogue well sub par and the romantic scenes are non-credible, but the good parts more than make up for this.
At the same time I am left with a disappointment, because it could have been so much more. Lucas is cursed because the bar was so high. He built an empire on that first movie but only delivered some of what he could. I'll get into spoilers in the after-the-break part of this posting, and here I'll speak more generally.
The entire new trilogy is the story of the fall of Darth Vader. This movie contains its climax, as he changes from troubled Jedi to evil lord. Powerful as it is, it's still not credible. Lucas had 8 hours of film all leading up to that one moment, so there's no reason it had to be that way.
Tied in with the moral fall of Vader is the more literal fall of the Jedi. As we know, they are betrayed, but that story too could have been much richer.
In addition, the biggest thing missing from trilogy 2 is the humour. Yoda, the imp who stole Empire barely cracks a smile in all the other movies. Almost nobody does. And the movies suffer for it.
On to spoiler-based discussionAnakin is drawn in this trilogy as a troubled youth. Yes, he has some flashes of pro-fascist statement, but by and large he understands his Jedi training. Then, at the moment of truth, he goes in just an hour from having moral ambivalence to slicing up entirely innocent children and his friends. It just isn't a realistic path to evil. Now, of course, the later movies suggest the dark side involves mind control, but this is never brought up.
Lucas missed the opportunity to tell a real story of a descent into evil. He could have created a Jedi order where the dark side was always present, always being played with by disobedient apprentices. The way normal teens are. Anakin could have had his own grand vision of how to make the galaxy better, not the muddled brief lines he says. Lucas could have studied better real men who became evil, or #2 evils, and their paths to it.
Instead he picks the plot that he does it for love. Problem is, due to poor acting and directing and dialogue, it's a love the audience doesn't believe in. Ditto for Padme dying of a broken heart, again it's a broken heart we don't believe in. Instead should should have died from complications from a crushed trachea. (I guess she couldn't name the kids if she were on a respirator.)
No, more naked ambition, and a lot more cunning would have made sense. And it would have been much easier if the Jedi and even the Republic weren't painted so well.
We learn of the Jedi from Obiwan and Yoda, its last two members. There's no reason that their version should not have been shown to be as distorted as their lie that Vader killed Anakin. I would have loved to have seen a much more morally ambiguous Jedi. They had great power, they should have been a bit or even a lot corrupt. The Jedi's own lack of corruption made them boring. Look at Samuel L. Jackson in a Tarantino flick and compare him to Mace Windu. Windu is one-dimensional, and we know the actor is capable of more.
Thousands of systems were leaving the Republic, and we're never told more than hints as to why, other than the manipulation of Darth Sidious. I barely understand why succession is something that deserves military response within nations, but it makes no sense if whole planets don't want to be part of a just government for it to go and force them to stay in. Tyrants usually arise because people feel they were a better choice than what came before. So why not make the Republic more evil, and the Jedi more corrupt. Then Vader's fall makes a lot more sense. Then throw in the mind control to take him to the next level of slaughtering innocent children coldly.
Of course the Jedi are arrogant. It seems crazy that they would accept this freshly delivered Clone Army that arrives just when they need it, ordered by a dead Jedi who told them nothing about it, cloned from a bounty hunter working for the Sith. Hello? Yes, they needed the soldiers to save them in the arena, but after that, they should have been freed. The immorality of this cloned army is staggering. That the Jedi agreed to lead it makes no sense. Moral as they claim to be, it would have been better to allow succession than to use it -- even without worries about secret agendas and hidden orders.
This would have been a good moral question to play with. The Jedi should have fallen for this arrogance and abandonment of principles.
Lucas didn't use my ending, but his ending was also good. I proposed that the best ending line would be "Did you hear that, they've shut down the main reactor? We're doomed!" which is the first line of the original movie. Tradition in serials was each episode showed a bit of the start of the next. The recreation of that scene (perhaps even a bit further to the never directly seen recording of "Help me Obiwan Kenobi, you're my only hope") would have left the audience cheering at the end. But the recreation of the double-sun scene was also powerful.
Of course, these movies were full of giant plot holes. We started in Episode 1 with the entire plot hinging on Qui-Gonn's inability, even with Jedi powers, to convince somebody on the entire planet of Tatooine to do some currency exchange with Republic credits. On a planet full of black markets! And many more like it. But these complaints above are not simply about plot holes, but about missed opportunities to do an even better story.