I already mentioned my conviction that the fact that the WotLK beta started in July means that we'll see the Wrath of the Lich King expansion still this year. I didn't expect anyone from Blizzard to confirm that impression, because they have a long tradition of NOT announcing release dates until the last minute. But Mike Morhaime just confirmed a Q4 2008 release by saying that WotLK will be out this year, and not in Q3.
Of course some people regard any current announcement and new feature of WotLK as a reaction to WAR. Warhammer fans are reporting that on Amazon WAR outsells WotLK in preorders by 3:1. But another meter shows that in total WoW makes 63% of all Amazon MMO sales, followed by Guild Wars with 16%, and everything else including LotRO, Age of Conan, and WAR at 5% or less.
I still believe that most current World of Warcraft players will buy Wrath of the Lich King. And a solid number of ex-WoW players will buy WotLK as well, at least to try for a few months before leaving again. *I* will buy WotLK to play for a few months before taking another break, as I don't believe the expansion will hold my attention for as long as Blizzard needs to release the next one. I think the current pre-order numbers aren't really saying much, many WoW fans will just buy the box when it comes out, and not pre-order it three months in advance. In my book Blizzard has a good track record in distribution, for The Burning Crusade you could go into a shop on release day and get a copy in most places. I think Wrath of the Lich King will sell around 5 million copies this year just in the USA and Europe. I don't think WAR will sell 5 million copies this year, and certainly not 15 million copies. The WAR preorders reflect hype and the fear to not get a copy on the first day, not a prediction of WAR ultimately selling better than WotLK.
It is now reasonably safe to say that we will have BOTH Warhammer Online: Age of Reckoning AND Wrath of the Lich King available before christmas 2008. Exciting times ahead, and not so far any more. But WAR vs. WotLK christmas sales will be just a first round in a battle which will still continue for several years. And while I am convinced that Blizzard will win that first round, they still have a lot of work to do to combat the impression that WoW is on the decline while WAR is on the rise. If the first expansion for WAR comes out before the third expansion for WoW, Mythic could well win the next round.