This has probably been written about before, and this is probably nothing new, like a joke about how Stormtroopers always miss or how episode 7 had some basic plot elements similar to episode 4. But this is my attempt to explain the reasoning of why I think [Star Wars: Episode VII — The Force Awakens](tag:711158) is actually pointing to Rey being the main antagonist of this trilogy and why that would actually make better storytelling in the long-run.
Rey Has No Moral Compass
When we first meet Finn, he destroys our expectations of what a Stormtrooper should be and how they should act. His refusal to kill and fight on Jakku gives what is known in screenwriting his "save the cat" moment. This is the moment where we understand who the protagonist is morally and ethically through a heroic act of kindness, an act that was not expected on an ordinary person in the situation. This is contrasted with Rey's lack of a similar showing of her ethical ideology. When we first meet her, she is scavenging, a fairly morally neutral act. When she first joins Finn, it is not in any way because she is against the First Order, but rather because the First Order is shooting at her and she must join Finn to survive. She is then brought upon the Millennium Falcon where she is fascinated by the myth of the force. She is told this is true, but the bewilderment in her eyes is still like that of a child who thinks joining the army would be cool because of playing with the weapons. Her moral compass never shows, and she seems to be living for her own best interests the whole time.
Rey Wants The Most Power The Easiest Way
Once Rey discovers her force abilities on Starkiller base while Kylo Ren is attempting to steal information from her brain in some force mind-game, she wants more power. This is acknowledged by Kylo who says she will grow more powerful as the time goes on. This is also recognized by Snoke, who requests that she be brought to him. During the torture sequence with Kylo, however, Rey decides to use her new power back on Kylo to torment him, to do the unethical mind-reading that Kylo was just about to do to her. When Kylo was about to read her mind and when he did it to Poe, it was made to be a clearly evil thing to do from a cinematographic view. The angles and shots, along with the music and emotion from Poe, made this act seem very evil, and yet Rey does this here to Kylo.
Rey Was Told To Kill Kylo By The Dark Side
In the official novelization of Episode 7, which is considered canon, a voice in Rey's head from the Dark Side told her to kill Kylo during their epic fight in the snow on Starkiller Base at the end of the film. This is most likely Snoke trying to lure her over to the Dark Side, a path he sees not too far off for her, as he can promise her the most power, if she learns his ways.
Rey And Kylo Will Switch
One of the obvious conclusions to draw from the movie was that Kylo will pull a Prince Zuko, and become the greatest ally to the protagonist from being the antagonist. This inner-conflict of the light and dark in him was made explicit through dialogue, and when he realizes the pain and suffering he causes, he will come around. This leaves the "bad guys" with essentially no major players with which to maneuver, but with Rey a dark force user, that will not be the case. She will probably be frustrated with Luke's training of her, or lack thereof, and seek greater power, and remember Kylo's invitation to the dark side. In episode 9, this will all lead to the final showdown of Kylo and Finn (and Poe) vs. Snoke and Rey. Finn will be a masterful force user by this point after he learns of his own powers. The force will grant him powers based on his extremely in-tune moral compass and desire to protect the universe. This is the major flaw he has in TFA, his desire to care for himself and he almost leaves Maz's because of it, but it is this type of character flaw in an archetypal plot-structure such as Star Wars that is the one most seen to change.
Films are no good when characters do not change, and characters will change more than just the pluck from normalcy that occurred in TFA, they will change in character and in alliances, as they find their true desire and role in the galaxy.