Wow, you really think that people will leave a game because of twits of some random man? I doubt it. Even if this random man is lead designer, I don't care about anything he says.
People (I mean those, who don't butthurt about GC and him being a lead designer, but those who actually plays a game) read these clueless twits and laughs, because GC says exactly same thing, you would say to these trolls. At least he is one of casual players, and most of these clueless posters with their reckless solutions about game balance like "NERF FROST MAGES TO THE GROUND AND MADE THEM UNPLAYABLE" or "REWORK THE WHOLE FROST SPEC COMPLETELY SO PEOPLE WHO ENJOY GAMEPLAY WILL REROLL OR QUIT GAME" wannabe hardcore players, are just bandwagons who gets carried by guild/raid and posts only to get attention to them, not to an actual problem.
Do you think that they just surf wow forums and answer on questions whole day? Or forum is their main source of their statistics and feedbacks? People who actually try to improve a game, never will post on forums, but will send them email.