With Kasdan and Ford having pushed for Han Solo to die in "Return of the Jedi", both involved in this new film, a set-up that seems to introduce new characters for the remaining films, I could imagine this:
- Han Solo dies in this film
- maybe along with Leia
- Luke cannot save them because he resisted the power he would get from the dark side - and afterwards... he surrenders to it and becomes the villain of this last trilogy.