Personally, I still feel like the “Palpatine trained Rey” route is the best path to go down. In order for the climax to be even mildly effective, Rey needs to learn something that both shakes the foundations of everything we thought we knew about her, and sets her up as a force of powerful darkness, almost destined to succumb to evil. The latest idea for that scene does the former, but it doesn’t do the latter: if anything, Rey learning that her parents were good people who sacrificed themselves to save her only gives her less of a reason to turn evil. Having Rey be Palpatine’s star pupil, heir apparent to the throne of the Sith, gives Rey an even more compelling reason to break bad than the original film did.