The main criticism of The Last Jedi is that it threw away everything The Force Awakens had set up. By the end of it there was almost no Resistance, no Snoke, no Luke (which might be a good thing considering what it did to his character), no payoff to the setup for Rey's past, and everyone who wasn't Rey or Kylo went backwards in their character arcs.

Just like The Force Awakens was hated by fans for throwing away the resolution of the original movies in order to set up A New Hope 2.0.

As part two of a three part series it fails miserably, especially if you factor in meta information like Kylo will be good by the end of 9 or Carrie Fischer passing. If you pretend it's a stand alone movie and not in an established universe, it's a bit less bad.

It killed every thread from episode 7, and didn't make new ones. It created major canonical problems with the Holdo maneuver and hyperspacetacking. It just copied empire, but in a slightly different order and threw in the throne scene from episode 6. It used the played out theme of the failures of the jedi, that the first 6 movies covered pretty thoroughly amd better. It declared Poe a failure, but the battle as depicted shows he was clearly right to get the dreadnought kill. The whole concept of the galaxies slowest chase, despite hyperspace existing. There's several instances of people teleporting for the plot, notably Rose saving Finn. The casino side plot to find a one of a kind super hacker, but a random guy in jail can do it too. The leaders of the bad guys are now Hux, who was turned into comedic relief, and Kylo, who has to be good, and was bested by Rey and Luke. Rey never gets training, and never fails (other than failing to get training), remains absurdly skilled with the force. Finn's character reverted from the growth at the end of the previous movie, and then had essentially the same arc.

The movie did have some really great looking cgi though. The holdo maneuver looks amazing. The red on crait is stunning.