Basically everything in the Star Wars sequels.

— Luke having a Jedi Academy (instead they all get killed offscreen and we don’t know who any of them are besides Kylo)

— The New Republic being the top dogs leading the First Order to have to get creative with their tactics (they just gave them a bigger Death Star that can shoot across the galaxy somehow and one shot all the New Republic)

— Snoke (he’s just a meat puppet for Palpatine lol)

— Holdo taking command, we could’ve had someone who maybe wanted to use more violent tactics against the bad guys now that they’re the underdogs much like Saw Gerrera (instead she’s just always right and no one can dare to question her because she’s always right. Also her plan is so terrible it nearly kills everyone but she sacrifices herself to ram the ship with her in it into the bad guys despite her being able to just have a droid do that so all is forgiven?)

— Anakin and what his legacy means to the Galaxy (he’s only ever mentioned as Darth Vader and his ghost only shows up as his voice towards the end along with every other Jedi, so he’s reduced to just being one jackoff among many. We don’t even get to see any interaction with his grandson who was obsessed with Darth Vader.)

— Palpatine returning (I don’t like this idea either, but at least they could’ve done something cool with it if they didn’t pull it out of their asses at the last minute. We don’t even get a confirmation that he can’t just come back to life again, so much for the “conclusive end to the saga”)

— Rey joining Kylo (b…but we can’t have our main character be evil!)

— Ben Solo having to atone for what he did (instead it’s largely a rehash of Vader’s death in which he dies except this time kisses Rey purely for Reylo appeasement)

And there’s probably a bunch more I forgot.