Ok. And? How long it took Blizzard is completely irrelevant, as this has become a standard for many players. Technology is not a hinder, not even close. As someone said, this game isn't competing with WoW at launch - it's competing with how WoW is today.
You might as well point out how long it took Ultima Online, Everquest or Anarchy Online to implement certain things. It has nothing to do with games developed/released in 2011/2012.
Let's say Samsung released a new mobile phone, which has the same features as Nokia phones had in the 90s. Would you buy it and then say "But it took Nokia YEARS to implement this technology (touch screen, 3g/4g etc)!". No you would not. You'd expect new phones to have the basic features of any other phone on the market.
But some people seem to have problems understanding this.