they had a chance to make Rey a very interesting character but decided to make her a Jedi Master without any training. 3PO, R2, and Chewie only do cameos in the new films. Snoke could have been interesting as more buildup and character development but Rian Johnson took care of that in the name of dumb plot twists.
All of the other characters introduced in the last two are forgettable. Sorry Lando can't save it. Even with the disaster that was TLJ Disney might have been able to salvage some of it if they had altered the plot when Carrie Fisher died.