I may be in the minority, but the sequel trilogy failed because they really failed to plan out Ben/Kylo Ren's story.
Starting him on the dark side required a much more compelling backstory than we got. Since frame 1 of the Force Awakens, we never really got a compelling story on how Leia, Han, Chewie, and Luke let him fall to the Dark Side.
The only explanation we got was Snoke in Force Awakens, who TLJ made into a joke.
Then TLJ made the answer that Ben final fall was because Luke tried to kill him, but we really aren't given a compelling reason why Luke came to conclusion. The implication is Snoke again, who the movie made into a joke.
Then we get to climax of Luke and Ben meeting again and while I can appreciate why they did what they did in TLJ, but to me Ben's fall to the dark side is because Han, Luke, and Leia were never there for him.
Then at the end, Luke wasn't even there for Ben. It just missed for me thematically.
To me the Force Projection Luke is actually too clever. You can have the exact same scene with Luke physically being there and drawing a much stronger the parallel to Obi Wan and Darth Vader scene in A New Hope.
Then you have Ben's abandonment issues being addressed in the movies with Han showing up for Ben in TFA, Luke in TLJ, and then Leia in RoS.
If Disney is interested in fixing the sequel trilogy, they need to make a movie or series showing Ben's fall and try to smooth out the connectivity issues between TFA/TLJ/RoS.
Kinda of like how Clone Wars/Rebels smoothed out the prequels by giving Anakin more depth.