I was never bothered by Rey's abilities in TFA, the way some fans were. What bothered me was that there was no acknowledgment that she was aware of her nature, nor was there any hint of what she wanted. In TFA Rey had just one stated motivation: to get back to Jakku so that she could maintain her apparently lifelong vigil for the return of her parents. That was it. Even at the film's end, when Starkiller Base was destroyed and Han was dead and she had fought off Kylo Ren, we didn't even know exactly why she went alone to find Luke Skywalker. Most assumed that it was to seek his training in the ways of the Force, but it was also clear that Leia was hoping for Luke's return so he would help fight the First Order.
So in TLJ, Rian Johnson addresses almost all of that in Rey's first minutes of screen time. He completely ignores her oft-stated desire to return to Jakku, and instead writes this wonderful exchange:
LUKE: Where are you from?
LUKE: No one's from nowhere.
LUKE: All right, that is pretty much nowhere. Why are you here, Rey from nowhere?
REY: The Resistance sent me. The First Order has become unstoppable–-
LUKE: Why are you here?
REY: Something inside me has always been there...but now it's awake, and I'm afraid. I don't know what it is, or what to do with it, but I need help.
This is more than we ever got for any kind of motivation for Rey in TFA, and it's really very welcome here. Johnson wastes no time establishing Rey's desires, and also the degree to which she is powerful. Luke sees her enormous Force potential, and he admits that it scares him. He resists the idea of teaching Rey, and she seems to be resisting a bit as well. Her real job is to bring Luke back to the fold, so he can reestablish the Jedi Order and help the Resistance. It's not certain at this point if she sees herself as a Jedi-in-waiting. She never states any desire one way or the other, except that she wants to know what to do with this thing that's inside her. Rey's entire story is her search for herself, and only at the end of the story does Rey find her purpose as she seems to be taking on the mantle of the Jedi herself. She will have to find her own way forward.
This fits in with what we learn about Rey. Through the Force, Kylo Ren sees Rey's lineage. Even though a lot of speculation after TFA had Rey being someone hugely important--she's Han's daughter! She's Luke's daughter! She's Ben Kenobi's daughter!--it turns out, at least for now, that Rey's parents were shitty junk dealers who sold her into slavery for some booze money and now they're dead in an unmarked grave. Rey's heritage is meaningless, irrelevant. The Skywalker Saga won't give way to the Rey Family Saga.
I wondered, the very first night I saw TLJ, if Rian Johnson was slyly alluding to Lloyd Alxander's Prydain Chronicles. That series is an epic fantasy about a young farm boy of unknown parentage who dreams of heroism and destiny and all that, even as he is drawn into the historical events of his age. He is certain he is of noble blood--the book's magic sword even seems to indicate that he is--even though his lofty position is that of "Assistant Pig Keeper". It turns out that no one knows who he is. His own master, a kindly and powerful wizard, found young Taran as a babe crying in a field, and even as Taran does eventually take the throne as High King he has no more idea of his heritage than he ever did. Likewise with Rey...and both this film and the Prydain books have a sequence in which the respective heroes look into magic mirrors, hoping to see who they really are, only to see themselves.
Rey's journey in TLJ also mirrors Luke's in a way, and Anakin's before that. Each at one point sets aside duties and imperil their friends by rushing into situations they shouldn't: Anakin's flight to his mother's side in Attack of the Clones, which ends with his failure to save her and his rage-filled slaughter of the sandpeople; Luke's rush to save his friends and confront Darth Vader on Bespin in The Empire Strikes Back. Rey's plan is to turn Ben Solo away from the Dark Side, just as Luke did Vader. (Quibble: How does she know that story? Is it common knowledge? Should it be?) This turns out to be impossible: Ben is fully committed to the point that he kills his own teacher in a Darth Plaguis moment--and just like that, the sides are drawn. Rey is given a choice here: Ben tempts her, but she turns away and chooses the light all on her own. She has chosen the Jedi path, whether she really knows it or not.
Yoda knows this, when he appears to Luke on Ahch To. That wonderful line of his--"We are what they move beyond. That is the burden of all true masters."--illustrates that Rey has made her choice and she is now moving beyond what Luke had to offer. As the film ends, Rey has been tempted and she has passed the test. She is frightened of what is to come, and she is daunted by the task, but she has found--just as Luke found--peace and purpose.
It's interesting to see where Rey stands, two episodes into her story, compared with Anakin and Luke two episodes into theirs. Rey isn't broken. She isn't defeated. She has all her limbs. She is determined and has a better grip on things than either of the previous two heroes at these points in their stories. This could make for an interesting starting point next time out...which depends on JJ Abrams, so all bets are off.
Next time: the villains. (Spoiler: I remain unimpressed.)