oh, you know.
This review may contain spoilers. I can handle the truth.
JJ Abrams helpfully put three metaphors for TROS into the movie itself.
1) a scene in which a character combs through some ruins from the original trilogy in search of a macguffin that will lead to that trilogy's villain
2) the reanimated corpse of the original trilogy's villain dangling from the strings of a giant machine, like a marionette
3) a scene in which a character returns from beyond the grave to explicitly disavow his actions from the previous film