Orange, you do realize that Blizzard has more than one development team right? The guys who are doing Diablo III are not working on WoW at all.
Crovax, you do realize that major development studios rarely have completely separate development teams and usually take a flexible approach sharing specialists between projects? So regardless of how large a studio might be the core teams are actually small and compromised of people with generalized skills, while e.g. model, environment artists, composers and whatnot are working on several projects at once.
Since different assets are developed at different stages of the game's design process you'd have people with non-universal skills sitting on their asses for 3/4 of the time and not doing anything, while you'd still have to pay them. The downside of this is of course that you MAY very well delay one project if you start pushing another one, which is exactly what happened here and what even Blizzard admitted in interviews with the press.
Bottom line: don't patronize people if you yourself have no clue.
Please do provide a link to where they said it. Would love to read it, so I can get more insight in the wonderfull world of gamedevelopment. I reckoned that WoW has its own design team dedicated to it, seeing they also turn out new free content reguraly. I also thought that the IT market is rather flexible and companies attract people as they go about making a game, and then get rid of them afterwards again. Artwork and stuff seems like a good choice for that. But you are the expert, so please shine your light brightly! For I am unworthy in the presence of such a god of reviewing games.
Goddamnit even though i try, I cannot manage to put as much text down as you in a post -_-. But please I would love to read that/those interviews