This Thursday comes the final Afterlives animated short – Revendreth – and introduction events are effectively done, so there is no need to stall the pre-patch any longer. I’d wager that video shorts release plan was aligned with pre-patch release date.
The next reset is September 22/23, which makes it about 1 month from the expansion release. Like many people, today I’ve got a friendly reminder e-mail from Blizzard that epic mounts of Ny’alotha won’t last forever, which is also an indicator of a certain impatience to announce the big news :)
I’d say that we should expect pre-patch date announcement this week, right after Revendreth release or in the next day.