Claremont established that Rachel was born before the Sentinels bodied all the heroes and the highest evolution of Sentinels were the Mastermold and not the Nimrod which goes to create the Black Brains so it's gonna take a lot of retconning to make this theory work.
Exactly. It doesn't match Hickman's timing and she was born and experimented on years prior to Nimrod coming online.
After Hickman's latest interview, I have at the back of my mind that Rachel might be revealed to be a back brain telepath. Would that piss people off or would people be okay with it?
After the end of this event and considering we didn't see the top of his head, the black brain telepath should be Xavier here. This is what I felt about him.