I am going to preface this review by saying that this is my subjective (and rather long) opinion and you can agree or disagree with me. Some spoilers included.
Overall, I was disappointed by this film in particular and the sequel trilogy more broadly. I agree with people who have said that this entire trilogy is at odds with itself - it truly feels like no one sat down to figure out the overarching plan for this. Specifically for The Rise of Skywalker, here is what I liked about it:
1. References to the original trilogy and the prequels - there were some really nice easter eggs!
2. The bond between Kylo Ren/Ben Solo and Rey, and Ben's redemption were done very well.
3. The visuals were amazing, as always.
4. Luke is more in character - this is how I would have pictured him in the sequel.
5. Leia's training as a Jedi is a nice touch to her overall legacy.
Now here are the things that I did not like:
1. Maybe I was not attentive enough, but Palpatine came out of nowhere with minimum explanation. While in itself it is not such a problem, it creates the two issues I will discuss below.
2. Snoke apparently was just a clone puppet of Palpatine's. To me this is the least imaginative way to explain him. Following The Last Jedi, why not say that Snoke tricked Ben and Rey and cheated death? Maybe even add on top that he is actually Darth Plagueis?
3. Once they announced that Palpatine was back, I was excited because I thought that Anakin would be back as well. They did not quite happen (aside from a voice appearance). To me this is problematic as it throws away the entire prophecy about the Chosen One + undoes Anakin's sacrifice in Episode VI.
4. Following the above point, I am disappointed that Rey was the one to defeat Palpatine rather than Ben. Would it not have "rhymed" better if Anakin's grandson had finished what his grandfather has started and thus would have achieved his goal (albeit on the light side)?
5. I have a quote for this one: "This is not how the force works, you idiot!" Seriously, force-transfer, bringing the dead back to life - everything is now on the table. In the context of previous films this does not make sense.
6. Leia's death: Maybe due to the pacing, but I did not understand why she would die from reaching out to her son. Was she that weak with the force?
7. The above point leads me to the next one: the pacing of the movie was so quick that many moments that were supposed to be emotional ended up not evoking anything because you had no time to process what had just happened. Many story arcs had to be dropped, and many characters got completely sidelined/not explored further. This movie raised more questions than it answered as a result (e.g. how is Rey a Palpatine? Why is Finn force-sensitive and where is he going to take it?)
8. In addition, many moments got so easily undone (like Chewie's death and C3PO memory wipe), or were so predictable (like Ben's death) that I felt no need to get emotionally charged.
9. Finally, episode IX tries so hard to distance itself from episode VIII that I feel it ended up shooting itself in the foot. Maybe that is why the pacing was out of whack (see point 7 above).
Is The Rise of Skywalker a bad movie? No. Is it a worthy conclusion to the story? In my opinion, not really. I guess they had to work with what they had. I will just stick with the original trilogy.
Thank you for reading, and may the force be with you.