Blowing up the legacy characters is a bad idea. Breaking with the past is a necessary one. A lot of flak TLJ now gets is rooted in TFA's derivative script rebooting arcs and story to square one thereby destroying the legacy. Thus:
Read my lips: No more rehash!- The Jedi Order is NOT destroyed by a young Emo-Skywalker again seduced by an evil dark-side Lord (this is embarrassingly uncreative fanfic writing and destroys the historic importance of the Jedi Immolation storyline)
- The Empire has NOT risen again and is more powerful than ever and builds the biggest & baddest (and easiest to destroy) DeathKillerStar evah (this ruins the achievements of the Original Trilogy and is embarrassing, uncreative hack writing)
- The Emperial Remnants can still play a role by e.g., controlling a fraction of the Galaxy (explain the situation!), but there must be a NEW KIND of threat, one so threatening that an uneasy alliance between Republic & Empire is required (have you ever seen Game of Thrones and how that works?).
Let it be something demonic, different and alien like the Dominion in DS-9 or the Shadows in Bab5, or even the Cylons or White Walkers in GoT.
- There may be a ideological/political dispute within the Jedi Order which leads to a break-up / new Force wielder movement (not: Sith!), and Luke fighting it realizing the the light side will always create a grey or dark side, thus an imbalance!
- If you must bring back kewl-as-shit smuggler Han back (in adult diapers) do it properly without destroying his arc. Eg Han misuses his position of power to help an old friend/embezzle funds because of gambling debt or whatever (he may be a brave war hero, but he is still a corrupt, greedy scoundrel). Han must then flee from authorities, thus losing his family and him going into the underground (not as a smuggler as he is a well known war hero, that would be TFA-level idiotic). Lea & al must renounce him (political reasons). Maybe the Jedi even hunt him (conflict). He hates it but must deal with it.
- Last, not least: PLEASE try to do at least a little bit of world building and new vehicle design so to differentiate this trilogy from the creative and imaginative masterworks that were the Lucas 6 (the Clone Wars (TV pilot) movies had more new stuff than the ST...).
I could go on forever with this, but creating something worthy of the Star Wars name would take time, money, recourses and the will entail creative risks and decisions. That's not what they go for so far. JJ Abrams instead of David Filoni (the out of wedlock son of George Lucas he created by manipulating the midi chlorians - but that is a story for another time).
