Not to comment too much on the validity of either situation, but given the constant ongoing cries of character assassination over hermit Luke despite that idea coming from Lucas, pre-dating both Rian and JJ, I can’t imagine the wider reaction to the idea that Leia started the First Order and was to blame for all of it all along. Even if it could track with her character arc, just the tarnishing of her good name so to speak would drive people insane. I certainly would be impressed with any edit that pulls it off, but just something to keep in mind.
There’s one benefit to give Lucas’ writing over Rian or JJ: Lucas listened to the actors and altered the character arcs and stories based on their feedback. There’s countless interviews from the OT where Ford or Hamill said Lucas was able to be convinced that their characters wouldn’t do X or say Y.
So hermit Luke indeed was a Lucas idea, but definitely would not have been executed as Rian did, especially given how Hamill was unhappy with the way the character was written. Even the cliche Obi-Wan “old master gives Excalibur and then dies” would’ve been a better way to end Luke than the contradicting yes/no/maybe mess from JJ and Rian.
Frankly, they should’ve both just let Hamill and Ford et al. decide their characters’ fates.