Blizzard views each of the "StarCraft 2" games as a very separate entity, with the single-player seeing the bulk of the new content in each release. "From a single-player point of view, they're going to kind of feel like sequels. It's going to be a pretty meaningful amount of content."
And what about multiplayer? "Multiplayer is going to be more like an expansion set sort of vibe. We're not going to ship all brand new races. There will definitely be additions to multiplayer, but that's going to feel like an expansion set." Pardo went on to compare the amount of new multiplayer content to what was added for multiplayer in "StarCraft: Brood War."