I actually liked his treatment in TLJ. Him and Rose had chemistry. Not having them become a couple in the third movie was beyond perplexing. They were one of the things that worked in TLJ
JJ went scorched earth on TLJ in the way that WotC went scorched earth on 4E. In JJ's case, it feels very much like he was mad at Johnson's choices, but if he had felt that strongly about it, he should have asked to do the second film to begin with.
I think one issue I had with it is it really undermines established movies to go in the democratization of the force direction because Star Wars is really meant to be a family saga.
That's a valid take, but I don't think it's the only take. Prior to people saying this post-TLJ, it never occured to me that Star Wars was
about the Skywalkers, so much as one father and his children were a key part of the story. It's a big galaxy, and I think for many fans, everything not-Jedi is what they love. (Well, until The Book of Boba Fett came along to explain that, no, you really don't want to focus on all that other stuff, either.)
The weaker moments in TLJ were when I could feel modern politics intruding. For example the way he kind of lampoons Hux (who in the first film was terrifying and you could clearly connect him to the rise of the third reich). It took out a very important threat (someone who could have even been a threat to Kylo Ren), in what felt like a punching nazis moment of the movie. I think Hux would have been far more effective as he originally appeared in the first new movie.
The way they handled Hux in all three movies was weird. Either Hux should have clearly been in charge post-Snoke or Kylo should have been. An interplanetary empire can't just run on inertia.
I do like Johnson as a director. The movie looks gorgeous. It just felt weird in places because of the way those ideas kept coming into the movie and it really felt odd having this movie sit in the middle of the trilogy.
The Empire Strike Back was
really shocking when it came out and incredibly controversial and did the same sort of smashing up the (much more limited) canon that TLJ did. It's just that took place decades ago now, and I think people don't remember that Obi-Wan being a liar and Darth Vader being Luke's dad and the hint that there was another hope if Luke fell were all wild changes to what we thought we knew at the time.
I think Johnson misjudged Disney, JJ and a large portion of the fandom in trying to pull of something similar in the middle of the sequel trilogy. "Rey is nobody," "we're killing Snoke halfway through the film" and "the entire Resistance can fit inside a single starship now" are all huge swings that I think could have really paid off if JJ hadn't gotten his nose out of joint and Disney hadn't screamed "for the love of God, just give them all the fan service," which didn't end up working either.