(A lot of these ideas aren’t mine, I just came across these on the Internet. I just think they’re great ideas that generally add to and improve the movie.)
The Force Awakens would retain its original title, Shadow of the Empire; this is to tie in more closely with the themes of legacy and how the actions of the Empire affects the current generation of the Star Wars timeline. It also refers to the First Order being the shadow of the Empire.
The crawl is revamped:
Luke Skywalker has vanished. In his absence, the sinister FIRST ORDER has risen from the ashes of the Empire and will not rest until the reigning REPUBLIC has been destroyed.
Among the few who heed the growing threat is General Leia Organa, leading a brave RESISTANCE. She is desperate to find her brother Luke and gain his help in restoring hope to the galaxy.
She has dispatched her most daring pilot on a secret mission to Jakku, where an old ally has discovered a clue to Luke’s whereabouts…
As the crawl finishes, the camera pans down to the forest moon of Endor, the capital of the New Republic. The scene depicts a fancy garden, a beautiful summer’s day, and a celebration. The Senate has gathered into a special session to commemorate the 30th anniversary of the Battle of Endor. A massive festival is planned, and leaders from all over the galaxy are there. The Chancellor of the Republic holds a brief speech recounting the events at Endor and of the past thirty years, everyone is enjoying themselves, and talking. However, one prominent senator is suspiciously absent. Leia Organa…
The movie cuts to the surface of Jakku at nighttime, where BB-8 rolls up into the frame and witnesses a First Order Star Destroyer eclipsing its moon and releasing four First Order transports, the film showing us shots of stormtroopers inside the transports as usual. The film then progresses as usual.
Wreckages of ships from the prequel era as well as remains of battle droids and clone troopers are there on Jakku, not only to further connect the film to the prequels but to reinforce the idea of Rey living in the aftermath of what has transpired in the saga and tie into the themes of legacy.
Unkar Plutt’s line is removed from Rey’s introduction sequence; as such, there is no dialogue whatsoever, up until Rey finds Teedo, having captured BB-8.
Reinstated deleted scene of Han hanging up the dice, to signify his reclaiming of the Falcon and to set up its importance in The Last Jedi.
Snoke’s visual appearance and throne are the same as in The Last Jedi, for continuity. Also, throughout all of his appearances he is shown with the yellow eyes Palpatine and Anakin (the latter in Revenge of the Sith) were shown to have, to show that he’s fully immersed into the dark side like how the other two were.
Since Hosnian Prime is replaced with Endor in this version, Ewoks, including Wicket, are seen witnessing Starkiller’s beam as well nearing the surface of the planet.
A binary beacon from The Last Jedi can be seen in the background during Rey’s last interaction with Finn.
C-3PO keeps his red arm through the entire trilogy (i.e. he never gets another golden arm); this is to play into the scrappy nature of the Resistance.
To start off with The Last Jedi, there are no “yo mama” jokes or anything, as it feels too… “modern” for a Star Wars film. Instead, Poe fakes a surrender and suddenly is when he starts his assault upon the Fulminatrix; this preserves the idea of Hux being a fool, while also preventing the scene from feeling too “modern” for a Star Wars film.
It no longer cuts to black when Paige falls, but rather a brief flash to white and an ear-ringing sound. Cutting to black implies a time skip and ruins the momentum of the scene.
Scenes in the movie are shortened for pacing and to avoid feeling too long or exhausting.
Snoke simply chokes Hux instead of ragdolling him around, to reduce the slapstick-esque feel of it, while also preserving the meaning behind Snoke punishing Hux.
Rey hears Sith whispers as the cave initially calls out to her, to emphasize the point immediately that it’s a dark side cave that’s calling out to her.
Instead of telling Finn and Rose about the Master Codebreaker, BB-8 tells them that their shuttle is being towed. That man in the casino is not the Master Codebreaker but rather a wealthy background character with no introductory music, whose indifference to them being tazed and dragged off serves to highlight the idea that none of the rich one-percenters even give a second’s thought about what happens to the lower classes.
Tweaked Rey’s line in the second lesson scene to: “That’s not true! You’re forgetting that —” It adds to the storytelling reason and necessity behind Rey reminding Luke that he redeemed Darth Vader.
I apologize if the following change sounds nitpick-y, but even nitpick-y changes can minimize small gripes with the movie. Luke doesn’t refer to Palpatine as his Sith title during his second lesson, just simply as Palpatine; this kinda acts as if Rey would know that Palpatine was a Sith. And even as its own trilogy, it better establishes what Palpatine, of all people, could do before we finally meet him in the trilogy, as Palpatine is never referred to as Darth Sidious in the following movie, specifically.
Luke references Dooku as well during his mention of Darth Vader, to back up his point that the Jedi unintentionally bring nothing but destruction to the galaxy. He also references that the Jedi “failed his father,” to add that it affected Luke, personally. “At the height of their powers, they allowed Palpatine to rise, create the Empire and wipe them out. It was the Jedi who failed my father and created Dooku and Darth Vader.”
As these are unreliably-narrated subjective memories rather than flashbacks to the actual events, both of the first two “flashbacks” start with a hard cut to black and then a fade in to help differentiate them from the rest of the movie.
After watching him casually slice his way out of the cell, Finn and Rose notice the red plomme bloom on DJ’s jacket and recognize him as the Master Codebreaker. DJ being merged with the Master Codebreaker into the same person supports the theme that, sometimes, you’ll have to work with people you don’t like, as well as the theme that people aren’t always who you expect.
Rey never narrates during the cave scene, aside from at the end when she tells Kylo Ren: “I’d never felt so alone.”
When Luke probes Ben’s mind in the flashback, Darth Vader and Palpatine’s voices are heard, breathing and laughing maniacally, respectively.
Ben uses his usual red crossguard saber against Luke upon catching him — either Snoke gave him the saber in secret, or he built it behind Luke’s back and used his blue saber to hide his affiliation with Snoke; his blue saber is still there, just on his table where he pulls his crossguard saber off of.
The deleted elevator scene with Finn, Rose, DJ and the stormtroopers is reinstated, but not in the way you’d expect. The stormtrooper who interacts with Finn is depicted as female, and would eventually become the same Jannah we see in the next movie. Rather than being comedic, this version of the scene shows that Finn feels recognized but for whatever reason the troopers don’t shoot him on the spot.
When Rey and Kylo Ren arrive in the throne room, Snoke is briefly shown in the middle of contacting a mysterious man attached to a machine. Snoke shuts the hologram off and turns his focus to Kylo Ren and Rey. The man in question is left ambiguous, only for him to be revealed as Palpatine in the next movie.
DJ doesn’t give Rose her medallion back. Why would he? The whole point of his character is that he only looks out for himself. (i.e. Rose is never seen wearing it for the rest of the trilogy, period)
BB-9E is not the one who contacts Phasma and the other troopers of Finn’s presence aboard the Supremacy; instead, when Finn, Rose and DJ are apprehended, the same trooper from earlier says, “I’m sorry,” implying she’s the one who reported them.
Snoke telling Rey she must die is replaced with: “And because of that, you are nothing to me.” It reinforces Rey’s insecurities, reinforces Snoke as the first embodiment of those, and also fits with and contrasts with the other two dark siders in this trilogy saying the same thing to her.
Kylo’s line about Rey’s parents in the throne room is altered to lean in more into them believing she was worthless and, therefore, shut all misreadings of her arc in the movie. “They were filthy junk traders who sold you off for drinking money. They’re dead, they drunk themselves to death in the Jakku desert. Your greatest fear is that you’ll be abandoned by the ones closest to you for not being good enough. Even Skywalker. As is mine. But the truth is, that’s exactly what you deserve. You have no place in this story, and you meant nothing to your parents. To anyone. You’re nothing, but not to me. To me, you’re everything.”
“Phasma’s End” is also reinstated, but not in the way you’d expect as well. Finn exposes Phasma’s role in shutting down the Starkiller’s shields, causing the other troopers, with the female trooper being the first, to point their weapons at Phasma, who shoots as many as she can down. Before she could have the chance to kill the rest, Finn engages Phasma in a fight, just like in the movie. This adds to Phasma’s cowardice and shows the first hint of Finn caring for the cause, leading up to, “Rebel scum,” while also not interrupting the main fight between Finn and Phasma.
New scene with Rey aboard Snoke’s escape shuttle, taken from in the movie’s novelization but is recontextualized to tie into her arc in this movie. She looks backwards, still saddened from her experiences, her realization that her parents, indeed, truly abandoned her, before calming down and suddenly facing the binary beacon on her wrist, with the camera lingering on it: “Home…”
Yoda’s scene with Luke is moved to right before the events on Crait, to hammer home the themes of learning from failure.
The porg scream in the Falcon chase on Crait is replaced with the one from the trailer.
I’m not posting any ideas about The Rise of Skywalker in this comment, maybe even this specific thread. That deserves its own thread, so people can have a “definitive” version of The Rise of Skywalker.