Look, this is easily a bit fan-ficy but has been something I've been thinking about for a while. Or at least it is the kind of sequel trilogy that I would much rather have gotten than what we did get. Maybe I'm the only one who'd want to see this but let me know below and say what you'd rather see with the two limitations being moving to a new cast and Han dying in the first flick since Harrison wasn't going to want to come back for more than one. Is this fan-fic ST era better, worse, or if you got something you think would be better post below!
Empire: The Empire, helped backed by the Chiss, now is run by an Imperial royal family and they hold territory mostly just in the galactic Core. The New Republic and Empire have tried to disarm to an extent so they both are using smaller cruisers than before, and the Empire is using craft more along the lines of the Gunboat or other multi-role craft rather than ties to reflect them not wanting to waste pilot lives or resources. Much more a humanized/benevolent Empire than the one seen in the OT.
First Order: A seditious force secretly led by the Snoke who plots to reignite galactic war. They use modified GCW surplus craft to reflect they have less finances being a small zealous force as well as using them as symbols of terror when operating outside of Imperial space. Basically sort of imagine them as a Cobra style group that wants to get rid of the New Republic.
New Republic: The reformed Republic that is largely led by aliens, especially those that significantly were a part of the GCW such as the Bothans and Mon Calamari, taking up territory from the Colonies to the Mid and Outer Rim. They use Incom and Koesayr as their starfighter contractors. Have them lean more towards the EU New Republic with some corruption and favoritism instead of being completely inept and then non-existent as they are treated in the current canon.
Jedi: Luke opened a Jedi academy that seeks to use what Yoda taught him and improve upon the past with adults being the ones to come become Jedi rather than children being taken, with the individuals deciding to take on the harsh and strict training to become intermediaries and settlers of peace. However at the start of the trilogy a number of their members have been killed while on missions for the New Republic as the FO seeks to weaken their ability to stop them.
Allied to Restore Peace (Probably needs another name): After Leia was forced to leave politics due to her being Vader's daughter she created a UN like aid and relief group that goes to the assistance of planets and systems to help get rid of pirates and later FO operatives. They use T-70 X-Wings as they are a symbol of Hope from the GCW along with other smaller support craft in their efforts to help others and because they are often fighting Pirates rather than large galactic forces. Leia is still connected to the New Republic fleet through Admiral Ackbar and Admiral Antilles who try to help her and Han out.
Kylo Ren: His twin sister dies while on a mission, wrought with grief he flees. It is then at this moment when Snoke seizes his moment and tempts the young man to the dark side, to make the galaxy not suffer the hardship he just had; but to do that requires sacrifice that being to return the galaxy to a galactic empire that can protect its citizens. So, Ben now Kylo leads the knights of Ren, warriors trained to eliminate jedi, goes about assassinating them when the New Republic sends them on missions. Kylo hates this but is misjudgingly trying to bring peace to the galaxy.
Rey: The princess of the Imperial royal family and heir to the throne. She is an advocate for peace between the New Republic and the Empire, and is trying to set up peace talks. She is force sensitive but not trained due to the boogie man nature that Jedi have been presented in Imperial media.
Very bare bones outline:
First Trilogy is split between a focus on the OT character to give them proper sendoffs (not killing them off aside from Han) and the new main focus characters. And would have to at least have one scene where the original three were able to be together on screen again. Themes of the trilogy being misplaced well intentions and the folly of not letting go of grudges.
Episode 7: Rey attempts to establish peace talks, while Kylo and his forces are sent to kill her to stir the Empire into action to attack the New Republic, though Kylo ultimately captures her he is smitten by her and instead hopes to get her to convince her father to begin the battle with the New Republic again. She is saved by Leia/Han’s task force with Han dying in the process and the tenuous peace if maintained.
Episode 8: Rey is being trained in the force by Luke and she has been meeting with members of the New Republic to try and open talks, all the while sending word of her success home, not knowing that it has been intercepted and stopped by the FO. Snoke uses her missing status, and some images of her in the New Republic as justification to the emperor that she has been kidnapped by the New Republic to be used as a bargaining chip. Rey finds out about her communications being jammed and tries to get back in time to prevent her father from starting a war, Kylo delaying her and her allies from getting to him. When she does arrive Snoke kills her father, declaring her the murder and how the New Republic had brainwashed her to be an assassin and that the FO would lead the Empire to get revenge. The act leaves Kylo questioning why with Snoke telling him how it was a necessary evil.
Episode 9: The galaxy is embroiled in open galactic warfare with Snoke leading the Empire in the interim until they can reclaim the former princess and free her from the ‘evil Jedi/New Republic brainwashing’. Snoke however just plans to kill her to keep the galaxy in this conflicted state. Kylo becomes more and more conflicted over the course of the film and when he sees Snoke try to kill Rey he kills the man instead. The big reveal being that Snoke was only intending on leaving the galaxy in chaos the whole time, not caring if the empire returned or not, just to weaken the galaxy for the oncoming threat. (way toned down Vong)
The Vong would be toned down so they weren't resistance/immune to the force but kept the unique and alien threat of living ships and weapons. And well they have been hinted at times in the New Canon too as a threat so makes sense to use them unless Disney/Lucasfilm plans to introduce some other force.
The second trilogy would more focus on the newer characters introduced in the 7-9 trilogy with OT characters mostly just getting cameos or smaller roles like Luke being there to still offer advice and guidance. But the trilogy as a whole would cover the heightened tension between the two factions, the Vong arriving and striking while the two were weakened and not willing to work together, leaving them in desperate states. However, the they are band together and the series ends with repelling the enemy force and the Empire and New Republic establishing an actual mutual peace agreement that returns the galaxy to a period of peace oncemore.
As for the reasoning of the two trilogies it is all for the cyclical nature of the first two trilogies. The PT leaves galaxy disabled and the formation of the Empire while the OT ends with hopeful peace for the Rebels. So the new ones match that theme with a destabalzing trilogy followed up by one leaving the galaxy in a state of hopeful peace and order.