Age of Sigmar: Missing Rules Already

So I know we are all really happy that GW entered the 21st century with an acceptance of the internet.  Think what you will about the Age of Sigmar rules they have made them available as downloads for the basic rules and the warscrolls for the individual models (the starter set scrolls have not shown up).  Strangely though they are on their second 75 dollar expansion book in 2 months  The first one I do not really know what is in it for rules but I think that missions/scenarios are what is being kept back from the internet to make buying it for more than just fluff/painting guides an idea. 

Now I have noticed that the Bringers of the Rotsmog is a bundle on the GW preorders as a new battalion but there are no downloadable rules instead referencing the new book out next week.  Is this an oversight or what to expect going forward.  Models have their rules which are free so far, but battalions and scenarios will cost you.  Obvious GW wants you to buy these books or they would not bother publishing them so I would not be surprised to see a lot of different variance in exclusive contents as the experiment to find the level which optimizing book and model sales.