Star Wars: The Rise of Skywalker is aiming to course correct Disney's sequel trilogy and win back the fractured fanbase, but that should not mean undoing The Last Jedi. Rian Johnson's Episode VIII had an infamously divisive impact upon the Star Wars fandom, and it'll be tempting for J.J. Abrams to try and appease those fans back by reversing so much of that, but ultimately it'd only serve to make both Episode IX and the entire trilogy worse.
It's difficult to know right now just what Abrams' approach has been in this regard, because The Rise of Skywalker still remains shrouded in secrecy. The teaser trailer didn't give a huge deal away - apart from the surprising return of Emperor Palpatine - but by, say, bringing the Knights of Ren back into the fold, we're seeing Abrams go back to ideas he first started developing with The Force Awakens.
If he strays too far down that path, then it's possible Abrams will make a Star Wars 9 that builds more upon where he wanted things to go after Episode VII, rather than where Johnson took them in The Last Jedi, and that would be a serious mistake.
Star Wars: The Last Jedi Broke Star Wars Fandom
Star Wars: The Last Jedi didn't just annoy a few fans or have a negative reaction that was forgotten about a few weeks after release. While some films only exist in consciousness for as long as they're in cinemas, The Last Jedi has endured, or at least, the debate around it has. Regardless of your opinion on the movie, the one thing people on both sides can generally agree upon is that it broke the Star Wars fandom.
There are those who love The Last Jedi, praising it for the bold moves it made, and those who hate it for similar reasons. Again, this isn't about which side is right, but the fact that that division has had a major effect upon the Star Wars brand. It's a franchise with mainstream appeal, but it's still not great to have so much negativity swirling around it, and the response to The Last Jedi surely had some impact (among numerous other factors) upon Solo's failure at the box-office.
Even now, a mention of The Last Jedi on social media can lead to a feverish, often hostile debate. There are life-long fans who maintain they won't see Star Wars 9 because of it, who don't want Rian Johnson anywhere near another Star Wars film and so on. Of course, Episode IX will be fine at the box-office, and Johnson's trilogy is still set to happen (despite previous rumors), but this is the backdrop into which The Rise of Skywalker is releasing.
Star Wars: The Last Jedi Ignored Lots Of J.J. Abrams' Ideas
One of the reasons some fans took umbrage with Star Wars: The Last Jedi was how it built (or rather, didn't build) upon the elements introduced in The Force Awakens. Abrams is a mystery box director, meaning he set up lots of things that were designed to be speculated upon, and that's exactly what the Star Wars fandom did. For two years, there were endless theories on Rey's parents, Snoke's identity, where the Knights of Ren were, what Luke had been up to, how Maz got the lightsaber, and much, much more.
The Last Jedi came along and struck them all down. Who are Rey's parents? They're nobodies. Who is Snoke? It's not important, and now he's dead. What about the Knights of Ren? Shrug. What's Luke been up to? He's cut himself off from the Force. How did Maz get the lightsaber? Still a question for another time. These elements work within the context of The Last Jedi: the reveal of Rey's parents is designed to hurt her the most, and that it does. Snoke's death is a genuinely shocking twist, and puts the focus squarely on Kylo Ren, a far more interesting villain. Luke becomes a much more complex character with thirty years of hurt. But they aren't necessarily what fans had expected or desired, and nor, it can be argued, do they build upon the pieces left behind by J.J. Abrams.
Rian Johnson received a bunch of mystery boxes, but for the most part decided not to even open them, instead choosing to do his own thing. That might've been less of an issue if Colin Trevorrow were still directing Star Wars 9, but now Abrams is returning, he's going to want his boxes back.
JJ Abrams Will Want The Rise Of Skywalker To Please Fans
Not only will J.J. Abrams want to reuse some of his ideas and plans that were either changed or ignored by The Last Jedi - such as the Knights of Ren - he'll also want to ensure this latest addition to the franchise gets the fans back on board. Abrams has a reputation for being a real crowd-pleaser anyway, but there are two big reasons why he might be looking to put plenty of fan-service in Star Wars: The Rise of Skywalker.
The first is The Last Jedi, and the response to it. As mentioned, it left the fandom broken, and Abrams has the unenviable task of trying to reunite it. One of the easiest ways to do that is giving them what they want. Secondly, this isn't just the conclusion to the sequel trilogy, but the end of the whole nine-movie arc that makes up the Skywalker Saga. It needs to tie off over 40 years of stories, but also satisfy fans of three separate trilogies and of all different ages. To bring this story to a close, it almost demands some degree of fan-service.
Fan-service isn't inherently a bad thing, but nor does it have to mean reversing The Last Jedi. Still, you can see how it might happen. Abrams has said there's more to the story of Rey's parentage, for example. Luke's return is shrouded in mystery (although not if Mark Hamill can help it). These are major elements where Abrams could adapt - or even outright retcon - what happened in The Last Jedi in Star Wars 9, which would no doubt please the fans who didn't like the direction it went in.
Undoing The Last Jedi Would Ruin The Sequel Trilogy
Abrams may have a few different reasons to reverse or retcon parts of The Last Jedi, but that itself is no guarantee of success. For all the fans he might please, there'll be others annoyed by the decision, so like with the Force, it's important to find balance. But more than that is, quite simply, that undoing The Last Jedi would make both The Rise of Skywalker and the Star Wars sequel trilogy as a whole a lot weaker.
Rian Johnson took the best parts of Star Wars: The Force Awakens - i.e. the new main characters in Rey, Kylo Ren, Finn, Poe, and BB-8 - and pushed them forwards in challenging new ways. In doing so, sure, he killed off Snoke and Luke, but he also left the door open for Abrams to go just about anywhere he wants. That's a genuinely exciting proposition to be built upon, especially after The Force Awakens stuck so closely to the template of the original Star Wars. The Last Jedi took the potential of Rey and Kylo and turned them into truly great, well-rounded characters, and things like Rey's parentage and the deaths of Snoke and Luke were crucial to that. Its core message was one of hope, even in the face of failure, and that anyone can be a hero.
For Abrams to change any of those aspects key to making that work would not only undercut The Last Jedi, but the broader themes that Star Wars movies have always played in. Episode VIII does ignore some of Abrams' elements, but it connects in the ways it needs to most (namely, those central figures), and what he adds feels like intrinsic elements of who these characters are and where this story needs to go. The true disconnect will come if Abrams does then reverse those decisions, making Star Wars: The Rise of Skywalker, the Sequel Trilogy, and Star Wars as a whole a lot worse off for it.