Two quick ideas. I’ve thought a lot about ways to alter Finn’s character arc, and while I do have some more ambitious ideas, I may have thought of two ways to change his arc with only some additional dialogue, at the least.

For Rise of Skywalker, what if we could create the implication that Jannah and the other rogue Stormtroopers were inspired by the story of FN-2187 to defect? In retrospect it feels like a missed opportunity for them not to do this. Maybe we could redub Jannah’s character, or find a voice actor that sounds similar to her, to say even one extra line of dialogue that goes along with this idea.

An additional idea for TLJ, what if we took the deleted scene of the Stormtroopers on the elevator, and redub the one that recognizes Finn to create an entirely new context. What if the stormtrooper(s) recognized Finn, but they let him go?

So in the second film you would have troopers who have heard of Finn’s defiance (maybe they especially like the fact he left Phasma in a trash compactor), and they defy the First Order indirectly.

And then in the third film, we actually see that Finn’s story inspired other stormtroopers to actually defect.

So although we don’t get to see Finn incite a Stormtrooper rebellion like we might’ve been hoping, we see how Finn’s actions have inspired others to defy authoritarianism. Which already plays well with Rose hearing his story in TLJ, and it parallels the themes with Luke and how his status as a legend inspires hope in others.