She wouldn't be writing it for you pressed fools that are about to be make ghostwriting jokes anyway.
I hope she'd talk about some of the more intimate struggles that it would be hard for her to explicitly say in an interview / documentary. I'd love to read about whatever she wants to reveal of her and Jay's relationship ups and downs, what it was like raising Blue, and maybe something about this miscarriage
It would be a best seller, naturally. I hope she does release a memoir at some point MUCH later in her career. I can see it being huge.