I forgot to talk about one more aspect of this situation, which is this:
A lot is riding on how good the ports of this game actually are. At the present time, far more people still have Xbox 360s and PS3's than next-gen systems. Given that NetherRealm Studios is not developing the versions for the older consoles, this means that it's critical that these ports be rock-solid and major-bug free, as they have the potential to comprise most of the sales.
NRS has had major issues in the past with companies porting their games to other systems -- Injustice Vita and MK9 PC both to come to mind. MK9 PC had big issues right out of the gate, and Injustice Vita still isn't as solid as it needs to be.
So if WB wants to sell the maximum amount of copies, they need to double down on QA and make sure that the kinds of issues that cropped up in previously ported MK and Injustice games don't happen here. Otherwise, being murdered in reviews and user impressions for the most popular consoles could put a partial damper on sales (see what's happening to the Battlefield franchise).