I can’t for the life of me find the YouTube video, but I wrote down some quotes from one Last Jedi review that I felt was pretty well thought out and not just a “rage bait” review, and one thing he brought up was this moment with Luke. This is a part of that review that I wrote down:
Something I see brought up a lot in response to this is that allegedly this is the kind of Luke that George Lucas had in mind for his episode 8. I don’t immediately see that as a problem and let me try to paint a picture for you. Let’s say that Luke had seen the darkness rising in Kylo, and even the future potential destruction that he might bring, and then said, “I’m Luke Skywalker, a legend. If I can save Vader, I can save this kid too.” And he does his best to save his nephew, and fails. Now THAT is the kind of failure might give someone as optimistic as Luke an existential crisis, making him retreat to his island of solitude in self-doubt.
If an editor were to take that approach, I think they could use AI dialogue to have Luke explain to Rey earlier in the film that either him and/or Leia saw a dark vision of Ben’s future when he was just a boy, and this was the impetus to begin his training (maybe this occur when Luke first tells Rey about what happened). But Luke, knowing the future is always in motion and having helped turn his father back to the good side, believes he can also help his nephew avoid this future. After years of training and guidance, perhaps Luke says that he thought he had changed his fate, but after sensing the darkness rise again he looked inside Ben’s mind to discern the truth, he realizes that nothing he has done for all of these years has changed anything. He may even believe that he made things worse by training him in the ways of the Force in the first place, so he might even feel responsible for creating Kylo Ren.
This change, while still similar to what we got, would illustrate that Luke made a lot of effort to try and help Ben, years of effort, and realizes that he still couldn’t save him. He breaks, has a moment of weakness, and thinks killing Ben might be the last resort to stop this dark force that he’s helped create. And even then realizes that he can’t kill his own nephew.
So I think it is important to clarify that in this version of events, Luke actually sees the vision years before that fateful night, and years later when he looks into Ben’s mind, he is either seeing Ben’s plans and/or another vision of the future that is even worse than the first. At this point Luke thinks he has failed, that Ben has already decided to become the monster in his vision and was preparing to betray him.
So to bullet point the timeline of events:
• When Ben was just a boy, Luke (and/or Leia) has a dark vision of his future, that he would become another Vader.
• Luke, believing the future’s always in motion, takes Ben to train him in the ways of the Jedi.
• Over the years, Luke makes a lot of effort to teach Ben right vs wrong, the Jedi code, etc.
• Luke is slowly lulled into a false sense of security, thinking he has changed Ben’s future, but Snoke has been secretly indoctrinating him.
• At some point, Luke starts sensing that darkness return. Suspicious, he looks into Ben’s sleeping mind to discern the truth, and realizes that Ben has already turned to the dark side and is planning to betray him and the Jedi.
• Realizing that he failed to change Ben’s dark future and is potentially responsible for enabling it, he momentarily contemplates killing Ben as a last resort to stop all of the suffering that’s to come, but stops himself when he remembers that this is still his nephew.
Really this would line up with what is already in the film generally, except that this makes it clear that Luke has made a lot of effort over years to try and save Ben from his vision, and is shocked to realize that nothing he did could change it. And this could require minimal change to the dialogue, depending on how you wanted to approach it.
(I have also considered the idea of Luke saying that he realized Ben was going to betray him that very night, to make the threat imminent and Luke’s actions feel a little more justifiable because he’s out of time to try and save him. Perhaps that would take away from Ben’s “innocence”, but he may have still been on the fence regarding the plan, or it became a self-fulfilling prophecy when Luke ignited his lightsaber.)