George Lucas said that "Empire Strikes Back" (ESB) is the worst of the 6 movies. This does not surprise me as the link notes that Lucas neither wrote nor directed the film. He might just be mad that he destroyed the entire series with the awful 3 prequels, made the terrible special editions of the originals and refused to release the untainted originals on DVD for years considering those special editions as the real deal, and in the 80s ruined Return of the Jedi by using the Ewoks and straining to make a Vietnam analogy. Seriously. E-f*cking-woks. Let's admit it, he was smart with Star Wars, got lucky to have a great director/writer combo to write the dark ESB, and it was downhill from there.
The sad thing is that he was so fortunate to have success, those first two SW films and then Indiana Jones in 1981, that he received a 30 year pass to make a mess out of his creations. Indiana Jones was salvaged by the fact that Steve Spielberg was the director. Without Spielberg, we never would have seen two other good Indy films made. There are countless mistakes he has made, but his fatal flaw is his vanity. He is so vain that he thinks he should be the writer and director. He is so vain, he wants to be the creative genius behind everything. Few individuals can keep producing new ideas and art for 30+ years. Lucas should have brought someone in to help him with the prequels. I vote for Timothy Zahn. Zahn knew how to work in the Star Wars universe, he knew how to handle Jedi powers without making them cartoonish, and would have had Lucas focus on the Force and the space opera. The greatest love of my childhood for pop culture was destroyed by one man's obsessive need for control and praise.