I actually suspect this is part of the problem The Last Jedi had, on one level it wanted to be a new Empire Strikes Back that tried to redefine what Starwars could be but ultimately it didn't really change things much at all, perhaps because Disney/Abrams didn't want them changed?
The problem for example with Luke just giving up and living on his island for example. The obvious alternative to that is that Luke really has gained some wisdom from the ancient jedi texts and his own soul searching. The most obvious direction to me would seem to be some kind of view of the force were negative emotions and the darkside are acknowledged more yet this would potentially upset the existing Jedi/Sith situation.
Equally the Rey/Kylo plot which was I think by far the best aspect of this film would also have potentially upset things if it was followed though on. If Rey either joins him or at least doesn't outright reject it then your also potentially meddling with the Jedi/Sith setup with the potential for these two characters to inhabit some kind of middle ground.
Honestly I think this was a significant problem the prequels had as well. If your going to shift your films focus towards characters like Anakin and Kylo then you need a more nuanced view of such characters. In the OT this wasn't an issue because it was Luke's character who was the dynamic focus and we got a more nuanced view of the "light side" to give it depth. Anakin flipping between heroic and "dark" like a switch just didn't work for me, didn't feel believable as a character, just making him a biut arrogant/petulant wasn't nearly enough.