My biggest issue with The Last Jedi, is the editing. The movie often had bad timing of scenes, and sudden unmotivated scene transitions. I recently watched this interesting video
regarding the editing of the original Star Wars. When George Lucas screened Star Wars to his close circle of directors for the first time, they hated it. It was an incoherent mess, but was eventually saved in the edit.
With the Last Jedi I noticed how it constantly cut back to Hux and the chase between the First Order and the Rebel ship, without there actually being a motivation to cut back to it. Nothing had changed, there was no plot progression, and yet we cut back to it several times. The Last Jedi also constantly cuts back to Rey training with Luke. And although Rey's adventures on the island are by far the most interesting part of the movie, it feels like these two parts of the movie do not connect with one another.
Then there's the timing of certain scenes. When I watched Thor Ragnarok earlier this year, I noticed how good the comedic timing was.
A scene such as "Get help"
deliberately has tight editing, with the camera stationary on the actors, and the dialogue sped up in order to eventually cut to the punch line. First Thor and Loki have a sincere heart to heart, to set up a serious tone. Then Thor suddenly says "Lets do: Get help", Loki protests, Thor insists, Loki protests some more - CUT to them doing "Get help" anyway. Perfect timing, and great editing.
I noticed in The Last Jedi how abrupt some scenes would change. One great example is Finn's fight with Phasma, followed by BB8's rescue by operating an AT-ST, then them all escaping on said AT-ST, and then abruptly being on a shuttle on their way down the planet. They skip the landing and immediately cut to the Canto Bight cops spotting their shuttle on the beach, and then immediately cut to them entering the casino, followed by a fast paced zoom through the casino. The pacing is all over the place. No scene is allowed to settle. And I especially found the AT-ST escape followed by the shuttle escape very jarring.
A similar problem occurred when Finn tries to escape the rebel ship and is discovered by Rose. She stuns him very suddenly, which then would be a perfect moment to end the scene and cut to something else. Yet they cut to Finn again being carried off. So sometimes it feels like a scene is over, but then it goes on and on.
This editing problem with the timing of scenes also translates to the timing of some of the jokes. The entire dialogue scene between Hux and Poe Dameron at the start of the movie, fell flat to me. There were a few awkward giggles in the audience, from people understanding that this was supposed to be a funny scene, and trying desperately to get a laugh started. But I feel its killed by poor editing and timing. Some other jokes (such as Chewy eating the Porg) did work, but the humor is very hit or miss. And I think this is partially to the way the way the scene is set up. When Poe talks to Hux, we're in the middle of a tense scene where Poe is trying to stop the First Order destroyer. And so the humor here feels out of place. It is not the right moment to crack a joke.
Then there's also the scene where BB-9E spots Finn, Rose and BB8. It felt like there was going to be (or should be) some sort of a confrontation between the two BB8-units, which ultimately has no pay off, and they are all just captured rather suddenly.
And that wasn't the only scene without a pay off... When Rey ventures into the dark hole, and has the surreal scene with all her reflections, the scene ultimately doesn't go anywhere. I guess this is supposed to be another twist, as if the director is constantly trying to defy the expectations of the audience. But some scenes need a pay off. When you have Rey ask who her parents are, something needs to happen. Either we get a shocking reveal, or she learns a valuable lesson (as Luke did on Dagobah when failing Yoda's test). But you can't just have the scene end, with no pay off, and no answers. That ultimately means her entire journey into the hole was pointless. And a lot of scenes in The Last Jedi are like that. What was the point of the entire casino planet, other than an excuse to have Finn and Rose get captured?