First off, highest priority is to re-hire the old authors and continue writing more books set in the old and vastly superior EU canon. Just have some kind of label declaring that the books and movies take place in separate canons and ignore the changes the new movies make if necessary.
Step #1. Ditch all actors from the original trilogy on grounds of age, contracts demanding they leave after one movie and ridiculous pay requirements. Hire new no-name actors who look similar to the original trilogy actors in their prime. Basically Star Trek 2009's trick only be even smarter about it and try to recruit from the existing Star Wars fandom to ensue familiarity and willingness to work for lower pay on the condition of literally starring in their favorite franchise.
Step #2. Create an adaptation of Heir to the Empire with Timothy Zahn in charge of writing the script and Mark Hamill as director.
Step #3. Continue adapting the rest of The Thrawn Trilogy.
Episode VII - Heir to the Empire
Episode VIII - Dark Force Rising
Episode XI - The Last Command
Next comes a standalone young Han Solo movie which is either an adaptation of Scoundrels or Han Solo at Star's End.
If Disney hasn't kicked me out yet, next will either be a Yuuzhan Vong Wars trilogy with a more H R Giger aesthetic than the "everything is made of lumpy coral, spikes, tentacles or some combination of the above" used in canon or a Knights Of The Old Republic prequel trilogy.
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If Disney refuses to let me do this and insists on an original story, I've also got a few miscellaneous ideas.
New characters:
Rey
A war orphan living on jakku and scavenging wreckage from the same battle which caused that state of affairs. During the attack on her home, she used the force for the first time in self-defense. Along with the chaos caused by Finn's defection, this is the only reason which there were survivors of the jakku attack. Simultaneously one of the only witnesses to the jakku attack and a potential jedi candidate. Also a potential problem if her first force use was something destructive like strangling a TIE Bomber pilot midflight and now she has an un-jedi desire to take revenge for the attack.
Poe Syndulla (yeah,
this guy with a green wig and name change to avoid licensing fees from the old EU)
One of Luke's new jedi, sent to investigate the attack on jakku, thus providing an actual explanation for his extremely non-military hotheadedness and tendency to treat orders as more like suggestions, he's not actually part of the new republic military.
Finn
All of Finn's best scenes as a character were the ones playing up his woobie nature, general unwitting heroism and adorkable lack of otherwise-common knowledge caused by having been abducted as a child during a prior raid as an unwilling stormtrooper "recruit". Furthermore what he meant as a character, effectively humanizing the stormtroopers while simultaneously making them back into a credible threat to protagonists. Having him suddenly start cheering on takodana when Poe is shooting down TIEs was completely out of character and the supposed deleted scene from TLG where he tries to convince stormtroopers aboard the Supremacy to likewise defect before Phasma killed them should have happened. His knowledge of the imperial remnant makes him extremely important.
Kylo Ren
The concept of Kylo Ren was one of the few genuinely clever moments Disney's writing team had. They knew everyone would be constantly comparing their villain to Darth Vader so they made that his chief characterization from an in-universe perspective. He's not Darth Vader, he's a mashup of an imperial equivalent of Luke's experiences in ANH, Cosmo Lavish but with Lord Vader instead of Vetinari and a crazed Darth Vader fanboy. He's got a homemade lightsaber and cosplay outfit, he tries to act as Vader-ish as possible, etc. If SB/SV have holonet equivalents, he's probably an active poster.
Making him the child of Han and Leia was the mistake. His parents should have been new characters, low-level bureaucrats in the Imperial system. When the empire was defeated, they were either killed in retaliation for prior abuses of their power or simply as collateral damage in the general chaos inevitable whenever a government collapses. Possibly go with some of the unused concepts for Rebels that had a relationship between Captain Vult Skerris and Arihnda Pryce to flesh out the universe and justify Pryce’s seemingly unprofessional hatred of Hera. His childhood was full of propaganda about how good the empire was and his experiences of life under the empire vs post-empire life effectively confirmed them for him.
Then the self-appointed Supreme Leader of the imperial remnant found him and more specifically, found that he was force-sensitive and offered him the opportunity to become like the "heroes" in his propaganda-fueled fantasies. The Supreme Leader doesn't think of him as an actual, proper sith, just as a useful idiot aimed at the Supreme Leader's enemies by fake praise.
His character arch throughout the trilogy is casting aside this joke of a character premise, killing the Supreme Leader and ruling in his place as a proper sith lord.
The Supreme Leader
Not "Snoke". Sith No One Knew Existed jokes aside, it was a stupid name. Besides, he isn't a sith or any kind of force user. He's a former imperial navy captain turned pirate, unable to surrender to the new republic since he's committed enough war crimes already he'd inevitably be executed. His "empire" is literally just a single deteriorating star destroyer which he keeps supplied by pillaging sparsely-defended minor planets and shipping and this is going increasingly wrong for him as his antique equipment continues to wear out and Luke's new jedi order mops up enough of the galaxy's more major threats to start prioritizing hunting down people like him. His only hope of getting out of this situation is Kylo Ren who thinks he's actually qualified as a sith lord and a bunch of fragmentary documentation about sith including a holocron he can't actually activate on grounds of not being force sensitive with which to maintain this deception and try to train Kylo enough to make him useful, not enough that the Rule Of Two comes into play.
TR-8R
A stormtrooper in Finn's former squad a bit upset about the whole abandonment and betrayal thing. Restores the generic enemy minions to being genuine threats. Based off how powerful jedi were in the prequel trilogy and some of the worst EU novels, Obi-Wan shouldn't have needed to sneak around Mos Eisley and hire a pilot but could have simply singlehandedly killed every stormtrooper in the place and hijacked a star destroyer. Survives the movie, although he loses an arm in the process. Will be back in the next movie, even angrier and with a prosthetic incorporating his anti sonofabitch stick.
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Jakku shouldn't be yet another desert planet. The moon of a gas giant, the gravity of which leads to absolutely massive tides. The star destroyer shipwreck goes from entirely submerged to exposed on a sudden beach. Imagine it encrusted with barnacles.
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No more superweapons. Fire any directors who are incapable of writing a plot without needing to resort to them.
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Ditch the inferior R2D2 knockoff, or if the marketing team absolutely insists, he needs to be redesigned. Yes I know there was a physical prop, but BB8 looks like bad CGI. Which is actually kind of impressive, given that it's a physical prop, but still, not something I want in my movie.
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No redesigned imperial equipment. Most of it looked stupid and the imperial remnant should barely have the resources to keep what they've got functional, let alone build bigger versions.