This post contains major spoilers for The Rise of Skywalker. I discuss the ending and everything.
After watching The Rise of Skywalker, my first thought is that the story in Jedi: Fallen Order was a thousand times better than this movie.
I came across a forum post suggesting that The Rise of Skywalker would have been a better movie if Jar-Jar had been in it. After recovering from the shock of such rank heresy, I read the reasoning, and it actually made some sense! The thought was that RoS really needed a single designated comic relief character. That would have had allowed the other characters to be more serious, which would have improved their part in the movie. Instead, everyone other than Rey is trying to be witty and tossing one-liners around, most of which simply do not work. The worst was when C3P0's gallant sacrifice got undercut with a snarky one-liner.
Rise of Skywalker is best summed by this Simpsons clip of Sideshow Bob. RoS is Sideshow Bob, and the rakes are mistakes. The movie just steps from one mistake to the next. Palpatine is a mistake. Palpatine having a thousand Star Destroyers is a mistake. Each of those Star Destroyers being a planet-killer is a mistake. Rey being Palpatine's granddaughter is a mistake. General Hux getting dispatched ignominiously was a huge mistake. (Hux is my favorite character from the trilogy, and it was galling to see him go out like that. Such a waste.) And so on throughout the entire movie.
Truthfully, I just don't like J.J. Abrams movies. I haven't since Star Trek: Into Darkness. It's all "action sequence, one-liner, action sequence, one-liner, etc." Sometimes I really wonder how the same man wrote Alias.
J.J. Abrams also doesn't have a sense of space and time. It feels like this entire movie took place in a small city instead of a galaxy. Instead of people moving across a galaxy, they're merely going up the street to a different neighborhood. That's why it seems like their paths cross all the time. The Force Awakens had a very similar problem.
Heh, I think Finn/Rose must have done extremely badly in China. It's super-conspicuous how Finn gets paired with a black woman this time around.
The one thing I did like was the relationship between Rey and Kylo/Ben. I really liked how their realities bled into each others. It was a superb effect executed beautifully. And they simply did not bother explaining it. They didn't know why it was happening, just that it was, and then they started taking advantage of it. For me, Rey's "crowning moment of awesome" was when she dropped her lightsaber behind her back to Ben.
The ending itself violates Sanderson's First Law of Magics. There's no real reason Rey should be the winner. She just is, because the Jedi are simply more powerful than the Sith for some unknown reason. As such, it is an unfulfilling ending. Rey should have won because Ben was redeemed, because there were two Jedi at the end. Something like Rey holding Palpatine in place with the lightning sabers, and Ben finishing him.
I don't really have an opinion on the kiss, which seems to be controversial for some reason. The connection between the two of them is pretty much the only good part of the trilogy.
I do think having Ben die was a mistake. This was the final movie in a trilogy of trilogies. Let it end well, with hope and redemption and forgiveness. Have the last link to the original movies, Leia and Han's son, survive. This idea that redemption is only allowable if the bad guy immediately sacrifices himself--that needing to forgive the living is not necessary or desirable--is a weakness in modern Western storytelling.
Ultimately, I feel like you could take the three movies in this trilogy, and cut out everything but Rey and Kylo's story. Reduce Finn and Poe to side characters who only occasionally appear. The resulting movie might actually be pretty decent.