Personally I enjoyed all 6 Star Wars movies. I am not amont those who express such bitter disappointment with the prequels. However, I cannot agree that the prequels are actually superior to the original trilogy.

There is an aesthetic principle sometimes described as "less is more". In a room with hundreds of decorative objects in it, the only aesthetic effect is likely to be that of clutter. Whereas, a room with just one decorative object invites your attention to that object, which you might appreciate fully as a result. The prequels are full of fascinating special effects but they are so numerous that it was difficult to fully appreciate any one effect with so many competing for my attention. In the original trilogy, the effects were wonderful; with those movies I felt that science fiction as a genre was being done in a convincing manner for the first time, after a long cinematic history of obviously fake effects. Each effect was meaningful, it was not there just to make the movie more impressive, or as a kind of eye candy.

It seems weird to me that you should say that the only good actors in the first trilogy were Leia, Han, and Palpatine. First of all, those are not actors, those are characters played by actors. The actors were Carry Fisher, Harrison Ford, and Clive Revill as the original voice of Emperor Palpatine (who was, of course, later played by Ian McDiarmid in the prequels). But what about Alec Guiness as Obi-Wan? Are you going to tell me he was not a good actor? And although Mark Hamill is often dismissed as an actor, he did have a quality of innocence that the movie required. I like the whole cast. The only unfortunate character in the 6 Star Wars movies is Jar Jar Binks in the prequel, who was not only insufferably cute, thereby creating a jarring note in what was otherwise a rather serious story, but also seemed to inadvertently suggest a racial stereotype through his odd diction and extreme servility.

You have pointed out various implausible elements of the plot of episodes 4 - 6, but they are no more implausible than episodes 1 - 3. I do not see how the well intentioned and decent young Annakin Skywalker suddenly turns into a remorseless killer who even slaughters all the children who are in training to become Jedi knights, all because the Emperor feeds him a line of rather obvious lies. Indeed, as Darth Sidious, he feeds obvious lies to everybody, and everybody believes him. The whole galaxy is apparently populated by credulous fools. Nothing in the prequels suggests any coherent reason for the Trade Federation to have gone to war at the behest of Darth Sidious (who, let's face it, is actually telling everyone he is a liar even by his choice of name, the insidious Darth). Similarly, I never had a feeling that there was even any plausible reason for Palpatine to be engaged in his campaign of galactic destruction anyway. He was perfectly successful even as the senator from Naboo. I understand that he was carrying out an ancient vendetta of Sith vs. Jedi, but why? It seemed very pointless. I also understand that the Force itself polarizes people, to either the dark or the light side, but that too is not explained. The Force is, after all, generated by organelles called midiclorians. There would not seem to be an evolutionary explanation as to why the midiclorians would form factions of good vs. evil. How could they even have conceived of such a thing? So there is a lot of suspension of disbelief that is need for the entire Star Wars series. You can watch it for the pageantry and spectacle, and the evocation of mythic themes, but not for logical clarity or plausibility.