Most disappointing aspect is easy: it is completely redundant.
Really, what was the point of it all? The ST was compressed into one movie already: Return of the Jedi. So I guess I have to give Johnson credit for realizing that when he made TLJ and killed off Snoke - essentially saying “we already killed the Big Bad Guy 2 episodes ago remember?” TROS undid this and remade ROTJ - thus undermining Luke’s character arc, as well as Anakin’s (for those who consider the PT canon). Rey is now just Luke…only better (or worse - since Luke defeats evil with Faith/Love, while Rey uses lightning). Thanks to TROS the entire ST is just a reboot of the OT. NO POINT!!
Quoting myself is lame, but I wanted to add this quote (from a youtube comment of all things!)
“If you don’t stop at Return of the Jedi, you have to commit to perpetuity.”