One point of TFA that really didn’t fit with Rey being a complete nobody was that she could understand wookies and droids. That is not a normal skill. Now that we know who she belongs with and can guess at her upbringing, it makes sense. And a few more pieces seem likely. I would guess from his running and hiding that Palpatine’s son refused to have children while his father was alive. I would also assume he was born before ROTS. So he married, and Rey was born sometime post ROTJ. Then he finds out his good ol’ dad is back from the dead and goes into hiding. So he probably lived on Coruscant or another core world and Rey must have learned to understand wookies and astromech droids there before they went into hiding. And it seems safe to assume that Rey’s father had no force abilities or he probably would have been Palpatine’s first choice. So it skipped a generation (unlike the Skywalkers).
I think that information maintains what TLJ had to say about anyone can be strong in the force. And the outcome of TROS definitely states that who you are is not based on your blood. Rey may have Palpatine blood, but she is not on the Dark side like her grandfather. And Kylo did not have to be on the dark side because of his grandfather. And TROS reveals Finn as the nobody who is force sensitive. So those themes carry forward even if Rey is now a Palpatine. For me it made sense, though so did her coming from nowhere.
And I read the leaked plot summary before seeing the film. I liked the plot summary and was excited for the film until I read the critic reviews. Then the viewer reviews started coming in an most were the same reaction I had to the leaked plot summary. And in the end, I enjoyed the film more than the leaked plot summary. There were a couple of things that the leak had that weren’t in the film. I wish they would have kept the Lando/Jannah plot, but they left it open to still exist outside the films. And I’m really not sure how this film had a more convoluted plot than the PT films. My reaction to those was that there was too much in them. That was not my reaction to TLJ or TROS. Both films had me enthralled and the time flew by. I didn’t feel overloaded at all. Overall I think that under Disney, Lucas film has made 4 outstanding movies and 1 good one. I think those 4 are better overall than what Lucas did with the PT.