Rey discovering her powers seems very much like the annoying midichlorian bullshit of the prequels that everyone hated since it turned being a Jedi from something you earn through training and hard work into favourable genetics. Why they would want to emphasize that in these new movies is beyond me.
I don't know how anyone could conceivably come to that conclusion. The movies, particularly the original trilogy, have made it very clear that some people are more attuned to The Force and that genetics does, in fact, play a role in this. "The Force is strong with him. The son of Skywalker must not become a Jedi." If it was
just training and hard work, then anyone could become a Jedi and there's nothing in the movies even suggesting that to be true. Leia was also shown to have used The Force to some extent, and there's no real reason why she should other than she's Force-sensitive since it runs strong in the Skywalker family.
Luke: If I don't make it back, you're the only hope for the Alliance.
Leia: Luke, don't talk that way. You have a power I don't understand and could never have.
Luke: You're wrong, Leia. You have that power too. In time you'll learn to use it as I have. The Force is strong in my family. My father has it. I have it. And... my sister has it. Yes. It's you, Leia.
Leia: I know. Somehow, I've always known.
Yoda was pretty much banking on this.
Obi-Wan: That boy is our last hope.
Yoda: No, there is another.
Also...
Yoda: Luke, when gone am I... the last of the Jedi will you be. Luke, the Force runs strong in your family. Pass on what you have learned, Luke. There is... another... Sky... walker.
Seriously, Ian, it's like you're not even trying.