Different opinions I guess. But I wouldn't say Luke had a dark streak. Yoda says anger and impatience which he shows in Empire, but by Jedi it is mostly gone except for a brief moment when Palpatine goads him. Canon has Luke as the undisputed hero until this point. Solo is the rogue, Leia is the moral bedrock. Luke was the hero. Now he is a coward. That's crap in my opinion, yours may be different. But there was no reason to do it.
Tent pole blockbusters, of which Star Wars has always been a banner example, are about simple, exciting things that appeal to the masses. What Rian Johnson made was not a tent pole film. And I think that is a huge part of the problem and where Kennedy failed to be the right steward for the franchise. She let Johnson get away from what appeals to the most and make a film that had too many themes that appealed to and angered different groups of fans, probably not equally, but closer than it should have been. That is simply a failure of what a tent pole movie is supposed to be. Even the prequels, as bad as they were, we're really only offensive for being bad movies. TLJ offended large amounts of people because of the themes and actions in the movie. And that is not what a Star Wars film should have ever done.
Marvel is reaping the benefits of tent pole films right now. We will see if they can stay on track after Avengers 4. Kennedy allowed Johnson to jump that shark and the pushback is apparent. We will see if Abrams can bring it back online or how a significant part of the fan base will react. I think if 9 is ok, all will be forgiven. If it's not, Star Wars luster will dim.
I wouldn't be surprised if 9 tones the story way back to traditional and blander statements. Disney can't afford Star Wars to drop off over the next decade. I suspect Abrams is less interested in Johnson's deep thoughts and more interested in another billion dollar gross. I also suspect Johnson, and Kennedy, get reigned in on that next trilogy, if he survives to make it.