It's nutty, but I think the Sequel Trilogy should've revolved around reincarnation.
Rey could've been Anakin, doing karmic penance for his misdeeds as Darth Vader, while Kylo Ren could've been Padme, understandably traumatized and unstable from seeing her husband turn on her, kill her, and commit endless atrocities in her name.
(Note: I'm not saying that 'Anakin' should've been literally played by Daisy Ridley or they should've brought Natalie Portman back to play 'Padme,' just talking about roles in the plot.)
Over the course of the ST, 'Anakin' could've successfully made up for his past and saved 'Padme.' I feel this would enhance the happy ending ROTJ already had and give the saga a final crescendo of Padme and Anakin eventually getting their happy ending. It would also explain 'Rey's' untrained proficiency with the Force--memories of 'her' past life as Anakin--and give us a reason to care for Kylo Ren besides 'him' being a Skywalker-Solo... we could probably get rid of that altogether.
This would also 'fix' how easily forgiven Anakin is at the end of ROTJ. Now, instead of redeeming himself with one sacrifice, we could do a 'Redemption equals life' where every trial he goes through in his new life is making up for his past and confirming his change of heart.
