About the famous reveal at the end of TESB: Darth Vader is Luke’s father, but it doesn’t imply necessarily that Vader is Anakin Skywalker. Besides, if you remove the part where Leia becomes Luke’s sister (it’s so obvious that Rey in TFA is what remains of the initial project concerning Luke’s real sister), it then becomes a lot easier to make prequels to the trilogy. Really, everything went wrong with RETURN OF THE JEDI (on every level: narrative, aesthetic, kids oriented tale, etc.). So, if you want desperately to have a 6 parts saga that does work with reveals untouched, you also need to make small changes to RETURN OF THE JEDI in order to erase the two problematic reveals (Leia and Vader = Anakin). Good luck with that…