I can't imagine them going F2P until WoW is all but dead. There's no way they can go F2P and maintain the level of support that they do now (yes, I know people don't think much of the level of support in WoW, but it's far ahead of where other MMORPGs used to be and perhaps still are). They also have a pretty big infrastructure to support. I think that it will be a while before they reach the point where non-subscription revenue would cover the game's costs.

Really, eleven million players is a heck of a lot. One third of that would be a heck of a lot.