Taking the idea of ‘symmetry’ and ‘balance’ a little further, what if one of the themes we’ve been missing is the relationship between the Skywalker and Kenobi lineage. In every episode of 1–6 there has ALWAYS been a Skywalker and Ben Kenobi at the center of the conflict in one way or another. With Ben/Obi Wan gone, someone would have to inherit that responsibility. To maintain that symmetry (and legacy), Rey would have to be a Kenobi. Kylo Ren is the Skywalker.