Blizzard's vice president of game design, Rob Pardo, has confirmed that if it weren't for World of Warcraft, StarCraft II would have been released a year ago.
Although Blizzard only announced StarCraft II in 2007, its development had already started in 2003. With the game's release scheduled for later this year, that would make almost six years of development with the single player part only being looked at halfway through development.

Quite impressive, hopefully we'll see all that work in the quality of the end product.

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