What Empire did was enhance the first movie.
In retrospect.
Given your age when Empire came out, you missed how big of a splash Star Wars made when it came out. My brother and I saw it more than a dozen times in the theater in the first year, and we were hardly alone. By the time Empire came out, audience members literally knew every word of the original screenplay (which is why so many older fans were upset about the story changes in the special editions).
And then Empire came along and announced that a lot of that wasn't true.
It wasn't a Highlander 2 rejection of the premise of Star Wars (which would have required, I guess, something like it turning out to all have taken place on Earth or something), but a lot of people felt that making the wise Gandalf-type into a liar was really upsetting and an attack on the core of the original movie, that the Rebellion getting its butt handed to it was a disturbing development and an intentional rejection of the hopeful nature of the first movie and I remember literal fights on the playground over the question of whether Darth Vader was telling the truth about being Luke's father.
In retrospect, all of that stuff worked out.
With a different third part of the sequel trilogy, all of those elements that seemed so shocking to people could have been seen as equally coherent.
But again, Disney, for reasons I would love to hear articulated by someone in the know some day, didn't think that any kind of pre-planning was necessary, either before or after TLJ.
But that isn't part three of a movie, that is the beginning of a new story. And it is a large scale political event, there isn't any clear line for the major characters the way there was at the end of Empire.
The ending of TLJ intentionally mirrors the ending of Empire. In both cases, the good guys are on their knees, a hero has fallen and the bad guys are close to total victory.
The ending of both films is fine. Trilogies often have a downbeat second part, just like many plays and movies have a downbeat second act. You need to give the protagonists a real challenge before the final victory.
And in another science fiction universe, something like this might be interesting. But a big part of the attraction to star wars is the jedi and the jedi order.
Yes. And yet, Andor and Rogue One and season one of the Mandalorian show it's not necessary for it to be the center of successful Star Wars stories.
Your complaints mostly boil down to "this didn't work for me," but you're characterizing them more along the lines of "this doesn't work, period," which isn't true, even if you don't agree with the folks for whom it worked for.
Also the thing about this at the end, while it is an interesting moment, it just feel more like a statement about what Johnson feels the force ought to be. But it doesn't lead my mind to speculate on what is going to happen next (because what would happen next seems like a deeply complex socio-political development and not a clear path to a story like Luke finding out his father is Darth Vader and Han being captured).
Again, different strokes for different folks. When Snoke got cut in half, it was literally the first time in decades (since Empire, to be precise) that I was surprised by a Star Wars movie and didn't know what was coming next. And I found that thrilling.
Obviously, different people want different things out of their Star Wars, which is one of the downsides of being such a massive hit. The audience for Highlander, in comparison, is much smaller, and their desires are largely the same: "Highlander 2 didn't happen, OK?"
I was a history student. Great man theory has been dead for a very long time.
Irrelevant, as Star Wars isn't written by historians. (For one thing, historians know to outline before writing.) Filmmakers can and do fall in love with largely discredited ideas from the past.