Instead of dragging Palpatine’s corpse back, use Anakin as the final ‘boss’. The confrontation on Mortis ends with Anakin Skywalker appearing to Rey and Kylo. Anakin has become the ‘Father’, intent on bringing balance to the force, and to achieve this he needs a Son (Kylo) and a Daughter (Rey). Both have been ‘destined’ to fulfill these positions and have felt the weight of external forces pulling them throughout their lives. Rey defies prophecy, choosing to leave and help the galaxy directly rather than watch from a distance.
That’s a pretty fucking cool idea.