And it's not just Rey. What exactly made Finn change? All it took was his stormtrooper buddy getting shot? That's it? The plot appears lazy. The characters have no depth. You really don't feel much for any of them, even the villains. The First Order, Hux, and Kylo don't have the same evilness and sense of dread you felt with the Empire, Tarkin, and Vader.
And it's the same recycled plot of Ep 4. They had a planet-killer weapon with some major vulnerability that the Resistance is able to easily attack and destroy the whole damn thing. They even had a droid carrying a secret message for the rebellion! The future Jedi hero is on a desert planet unaware of their destiny. It's all been done already. Did JJ Abrams get messed up and thought he was doing a reboot instead of a sequel? I've seen A New Hope dozens of times since I was a kid! I wanted something different. What's Episode 8 going to be about? Will it copy Empire Strikes Back? They might as well call it First Order Strikes Back!
One other problem with the plot...they destroy five planets with their weapon. But they don't destroy the planet with the base? Isn't the common sense strategy of war to take out the defense capabilities first? Who the hell destroys the Senate before the military?
I know Disney just wants to make some money. But geez, they could at least come up with a new idea or some characters with more depth.