I want TLJ to reveal that Rey has been using her force abilities to learn how to speak wookie, droid, pilot old ships she's never seen, and all that other overpowered shyt she did in TFA to cope with the fact her mommy and daddy left her on a dirtball at like the age of 6. She's a perfectionist to an insane level because she thinks her parents left her because she wasn't good enough and being amazing at mad shyt was going to be her way to gain their approval when they came back.
So you've got somebody who spent their whole life as a perfectionist looking for acceptance from the legend Luke Skywalker who wants nothing to do with her no matter how amazing she is and that resentment that Rey has held in all those years bubbles over.
They probably won't do that but it would fix some of that overpowered amazing at everything stuff from TFA for me.