So the lesson in the sequels is finally what it should have been all along: defining yourself by your attachments (Rey Skywalker) is a really good thing, even as a Jedi, but you have to have the strength to let go when the time comes. And to not fall into hatred or anger when they are taken from you (Anakin and the Tuskens). It was actually George’s intention to convey this lesson through Star Wars, I believe. Hopefully Rey’s new Jedi Order differs from Luke’s in this way for her upcoming film. It kinda sucks that in the EU this was precisely the lesson Luke incorporates into his own new Jedi Order, but this is the path Lucasfilm has chosen, so it’s best to just embrace it at this point.
If you want to seed this idea earlier, you can include part of Anakin & Palpatine’s opera scene during Rey’s vision in TFA after she touches Anakin’s lightsaber:
“The Sith rely on their passion for their strength. They think inward, only about themselves.”
“And the Jedi don’t?”
It both sets up the final lesson & sets up Rey’s tendency to go straight to the dark, especially if you’re using Starlight as a baseline.