Disney revealed the original plan for the sequel trilogy and it turns out J.J. Abrams wrote most of it but it was deconstructed and morphed into something different by Rian Johnson. They say that Luke was supposed to live until Episode 9 and be in Episode 7 but they wanted everyone to focus on the new characters Abrams had written more about Luke and the almost non-existent Knights of Ren.
Rian obviously chose to go a more interesting route. There are drafts already done for all 3 films but when Rian was selected to direct the middle film, he met with J.J. Abrams and decided to not go with anything of what J.J. had already written. There are even more unanswered questions than there was when Episode 7 which is a problem for Abrams since he’s on some major clean-up duty. On top of that, Star Wars fans are ruthless. Kathleen Kennedy needs to be a bit more careful in what she lets directors do if she plans on keeping these films successful and enjoyable. We’ll have to all wait and see what miracle J.J. whips up for us when Episode 9 comes out.