My theory is, they got the bad news on about the House of Wolves out of the way early, so they can roll out a steady stream of much better news - meaning, what's in it, rather than what is not - over the course of several weeks and try to turn the PR around over that time frame. I think they knew that anything they announced or detailed in tandem with the raid news would get buried in, well, what's been happening.
Look at what is first on deck: the upgrade path for gear in the new expansion. That was the primary source of outrage in the first expansion, and Bungie is said to have taken a very different path that reflects that reaction this time around. After that they get into the actual content of the DLC. I think the hope is, by the time it's released we'll have a fuller picture of the package, and enough time will have passed for the initial no-raid rage to have dissipated a bit.
Personally, I'd have taken a similar approach - let the raid news blow up/over this week - and then lead off with Prison of Elders, which while not a replacement certainly is filling in a similar endgame role in HoW. Saving it for last is a mistake, IMO.
It's pretty clear Bungie is listening to the community, especially in the last few Destiny updates (which is why they knew they would get clobbered for this); I hope to see that reflected in the rest of the HoW news.
No, they have not even mentioned the next update. The last one just came out.
Edit: oh, HoW updates. Yes, my bad. :lol