This is an enormous “if,” but if they do, may as well go balls to the wall.

To me it’s too late for IX to introduce or do anything radically new, so I’m just hoping for a thematically appropriate conclusion to the stupidly-now-called “Skywalker Saga” (“because now we want Star Wars to include space-stuff that has nothing else in common but their titles”) in the vein of “see, kid,
I knew you could do it, and the lessons you learned along the way will always help you.”
Basically, if the whole saga is ANH, IX would be the part when Luke flies back down to the Rebel base and hears Ben tell him, and the audience, “The Force will be with you… always.”