This has probably already been said somewhere, but given what we know from the trailers, other sources, and basic cinematic tropes, I can predict one of the crucial plot element at the Star Wars: The Force Awakens. We know Luke Skywalker is in exile for some reason. He’s in the second trailer (see screenshot above), with R2-D2, in front of a bonfire. He may be in exile because he’s being hunted, or maybe he reasons becoming an active Jedi will elicit a Sith Jedi to emerge, in order to maintain balance. I don’t know the universe mechanics too well right now to be sure.
There’s the revived Empire and the new rebellion, the Resistance. Given the subtitle of the movie, too, I’m going to say Luke is convinced that he needs to take up the Jedi mantle again, in some form or degree, to meet the growing power of Rylo Ken and the Empire. A final scene will show Skywalker taking up his lightsaber once again (Leia has it…see link above) to set things in motion.
Not a giant leap of a prediction, since Star Wars is riddled with reluctant heroes, like many sci-fi media. Just some food for thought.