Yeah, there is definitely something deeper to Rey we haven’t seen yet and I feel she’s as much a “mary sue” as Luke and Anakin were to their trilogies. Since she is the same character as both Anakin and Luke, it follows that she is the Skywalker of the new series and therefore must be Han and Leia’s daughter and Ben’s sister. I digress.
If you want a real “mary sue” look no further than Rose.
Perhaps it’s the real reason behind the everybody else’s hate for Rose, I don’t know but, it is the reason behind mine.