[Shaman]

At the end of Return of the Jedi, everyone becomes a good guy. This is a problem because there is no more dark side to counterbalance the good side. In short, there is an imbalance in the force.

If there had to be an Episode 7, it would have to be about a resurgence in the dark side. And since Leia is a weak untrained Jedi, then such a movie would just have to be made with Leia getting sucked into the dark side.