Non-Spoiler Review
People who have issues with this movie I'd argue really don't have a better understanding of the universe itself. Every Star Wars movie has it's minor plot holes, but I am referring to much bigger complaints people are giving about the movie. There are several things that need to be known before seeing this movie - and a lot of it has to do with the understanding of the prequels - so if you are going to see this movie please read what information I am going to inform you of below
1. Understand that Palpatine created Anakin Skywalker in the prequels. In Episode 1 it is revealed that Shmi Skywalker birthed Anakin as a virgin, through her discussion wit Qui Gon Jin. This is further backed in Episode 3 when Palpatine tells Anakin that Darth Plagues taught Palpatine how to create life. Be mindful of this when watching Episode 9.
2. Watch The Clone Wars animated series. The character development of the Jedi council and knowing who they are and actually caring about their characters will make an important scene of the movie significantly more impactful. You WILL NOT appreciate this scene without getting to know the Jedi of centuries past.
3. Just because new Jedi powers never seen on screen before are shown in the film doesn't mean they've never existed. All of the force abilities in this movie have been done in previous book and comic titles.
These 3 points are crucial to understanding the film. With that being said; whether you view this film independently of the franchise, as the closure to the sequel saga, or the closure of the franchise itself - it is an extremely beautiful movie with an actual good script unlike Last Jedi.