The thing that has bothered me since the PT is that if becoming one with the force and becoming a force ghost is something that you have to learn, how did Anakin accomplish it? The PT sets it up that this is something Ben and Yoda have to learn and that Qui-gon didn’t manage to learn it completely. So how does Anakin do it? Did he start looking into it after Ben vanished? Or is it because he is the chosen one? If he is the chosen one his job isn’t finished and he should appear in this last film. To me, the ST doesn’t exist to close out the story from the OT, but to wrap up the extended story that the PT started. To me balance in the force mans light and dark sides together. The concept of the force being out of balance seems to originate with TPM and the PT doesn’t really give enough for it to feel balanced after ROTJ. At that point all the good and bad of old have been wiped away and there is just Luke. But to really finish off the story as it was expanded in the PT, we really needed to see how it gets balanced and the current story seems to be headed that way. TLJ was filled with it and so was TFA. So even if the title of the episode isn’t Balance of the Force, I expect that to be a one line summary of the story.