Just off the top of my head
- I'd give Luke a son, but he's not a Jedi, he decided just to be "just a civilian" basically and Luke was OK with that. During the course of the story though he may be pushed into action.
- I'd include a character that dabbled with the Dark Side and fringe elements of the Force, but ultimately rejected it and is now a regular Jedi. Idris Elba would be my choice for this character, I think he'd be interesting. He's a "good guy" just with shades of grey. He's kind of an "out there" character as part of his back story was he was drifting/lost in space for decades.
- Luke has strived to keep the details about Darth Vader (most notably that he was Luke's father ... someone who commited all sorts of war crimes) under wraps, but it leaks and Luke is forced to step down as head of the New Jedi Council.
- Han has a story arc with his daughter and Lando exploring the organized crime/underground world of Star Wars. They're working to get Luke out of trouble and find out what's really happening.
- There seems to be an "architect" type villainous force ... think The Joker in The Dark Knight Returns, without the crazy persona, someone cold and calculating and suddenly the galaxy is rocked by chaos and scandal.
- The New Jedi Order isn't as stiff or uptight as the old Jedi Order, per the way Luke has set it up.