I don't buy that Rey is a nobody with drunk parents. Consider the source.
I buy it....
I kinda figured they'd go this route as more promotional material was released and it seemed to indicate she wasn't a Skywalker. Rey even thought she might be, according to Kylo "you're not one of us" or some such... "You're nobody.... nothing."
It's a more profound way of democratizing the idea of the Force.
Think about it this way... Rey is the little boy at the end of the film who uses the force to grab the broom... The movie ends on him, because he
is Rey, at least, metaphorically speaking. His parents are wholly unimportant, because you don't need to come from great parents to do great things. I think that's what Johnson is trying to change about the Star Wars mythos.
And talking about change... The entire point of the movie is that we should "let the past die," and that the Jedi aren't texts, or even people, but an idea... These ideas are more powerful than ships, or fleets...
For example, the legend of Finn is more important than the real Finn, because it inspired ...the Asian woman, I'm sorry, can't remember her character... it inspired her sister to sacrifice herself to destroy an Imperial, sorry.. First Order Dreadnought. That same legend then inspires the Asian woman to become a hero herself... and also to fall in love over the course of 8 hours (remember this whole movie takes place in one day).
So Rey being a nobody is a plot twist that forces all of us to erase the notion that Anakin or Luke, or Kylo for that matter, are somehow better than anyone else by some kind of Divine Right. They're not. Because a slave girl, who was "nobody." ..from "nowhere" is truly the greatest Jedi of them all, at least.. for the time being.
She's not the daughter of Obi-Wan, and Luke never met her. She's never been trained, and nobody knows who she is.
If you really really wanted to twist shit around, you could argue that, like Anakin, she was born from the Force itself, and perhaps some slave woman birthed her and gave her up... but... As far as I can tell, that's not where this movie is going. Not thematically, and not expositionally, again, as far as I can tell.
....
p.s.
With all that being said, I think it's a horrible direction for a mainline Star Wars film. Because, there's just no way you can turn this around in one movie in a realistic way. The First Order has won, the Empire is back, and the entire galaxy has accepted this. They achieved this end WITHOUT Starkiller base or a Death Star... the fear they've imposed on society is what Palpatine always wanted but could never fully grasp.
It's almost as though someone watched Star Wars and said .. I'm going to turn all of these ideas on their heads, wipe all of this out, and force them to start over (the entire mythos); and I'm going to do this because it'll make for a more profound movie... which, I think instead, Abrams just ends up remaking Return of the Jedi and this trilogy would truly have been meaningless.