If EP8 reveals that Rey is related to someone we already know, this will be downright ridiculous.
Then you must really hate Leia turning out to be Luke’s brother in ROTJ.
There is a huge difference between what ROTJ did and what new trilogy is doing. As being part of the same trilogy, it was ROTJ’s job to develop the concept of Skywalker family that was merely briefly introduced at the end of ESB (admittedly it overdid it with Leia but okay). On the other hand, new trilogy is shamelessly directly copying concepts from OT.