One theme that I'd love to see as an overarching motif is the difference between "peace and justice" (as the Jedi serve, per Obi-Wan) and "law and order" (as all governments must serve, be they Republic or Empire). Law is not necessarily justice, and order is not necessarily peace, and Leia (the Senator), Han (the smuggler), and Luke (the Jedi) would each have very strong opinions on the subject --there's
your wedge issue to drive between Han & Leia.
The raw material is already there in the Sequel Trilogy's makeup; the smaller, leaner New Republic lacking the resources to serve the Outer Rim, the First Order stepping in to "protect" people from roving bands of pirates and rogue nations --people (as we see in Resistance) eagerly embrace oppression because they think it means safety.
Maybe have the Resistance headed by Lando, as a sort of mirror-image of the First Order, both providing protection to those the Republic can't serve (for a modest fee, of course, because Lando
Luke's Jedi are in isolation (Aich-to isn't a hermitage, it's the hidden Jedi Academy), Luke having experienced a (Prequel-inspired) epiphany; that the Jedi cannot be tied to any government for fear of becoming pawns as they did in the Old Republic. Luke's Jedi are not generals or diplomats, but wandering Kwai Chang Caine
-like do-gooders, and there aren't more than a dozen or so across the whole galaxy.
That's how Kylo Ren ended up with the First Order --no one realizes that it's Ben under the mask, having gone rogue after buying into Snoke's rhetoric about bringing order to the galaxy.
The first movie is about Lando and Leia trying and failing to get the Republic to intervene; Lando convinces Han, Han convinces Leia, and Leia. . . finally comes up against a force that she can't move through shear force of will. Meanwhile, Lando's newest protege, a renegade stormtrooper, and a scavenger discover that there's a Dark Jedi running the First Order. Maybe Maz Kanata can be one of Luke's Jedi, who brings Rey with her to Luke's Academy, while Poe and Finn team up with Leia's volunteers to destroy the Starkiller.
The second movie is mainly about Rey on Aich-to, and Ben returning and having his final confrontation with his master as he reveals his dual identity and tries to recruit the other Jedi. Those who won't join him perish in fire, and Luke gets to have his Obi-Wan moment, buying time for Rey (and Maz?) to escape and join up with the Resistance.
The third movie can be about Han confronting his son (and the other Knights of Ren), and Rey destroying the First Order --still leaving a power vacuum in the Outer Rim, meaning there'll still be years or decades of work ahead of the young heroes, with only minimal support (i.e., periodic cameos) from the surviving oldsters.