In execution, I believe that bringing back Kylo Ren from the dead for a sequel movie would be similar to Emperor Palpatine’s return.
Can I also bring up that resurrecting Kylo Ren would essentially be bringing one of the greatest war criminals of the Star Wars universe back to life?
It’s really only a move Rey would support, and no one else.
Mainstream audiences wouldn’t understand it, a movie wouldn’t be capable of spending the time to explain it, and you run the risk of a good number of people thinking it’s a dumb departure from the franchise.