Honestly, Johnson could probably adapt some of the ideas he might have had for the Looper universe at that point: Widespread acknowledgement/acceptance of telekinetic powers was a key aspect of that movie’s worldbuilding. Repurposing some of that but making it The Force could be interesting. Imagine a Star Wars universe where “everyone can tap into the Force to some degree or another” isn’t just an idealized notion, but a reality within the fiction that simultaneously complicates and normalizes the energy force and makes it a little less mystic, but no less mysterious.