Well in that case...BRING ON THE DLC! We needs some extras for our books.
Let's publish an incomplete book and tell the readers, for more money, they can have the rest of the book.
It just wouldn't make sense to have it out after Skyrim, if the events effect the future direction then the general ending would be spoiled.
The Penitus Oculatus were afraid to go to Skyrim. That was Keye's way of saying, "can't talk about it."