Speaking to Eurogamer last night at BlizzCon, Production Director J. Allen Brack stated that Blizzard has no plans to make World of Warcraft free to play. "We didn't make the game to be free to play," he said. "We would have to rework the game pretty significantly in order to make it free-to-play. It's not something we're currently considering."
This echos what Mike Morhaime said in an interview on the BlizzCon Virtual Ticket. He also said that WoW was not designed to be free to play.
Many had thought that with subscriber losses and the introduction of an in-game Blizzard store on the PTR that WoW might be heading toward a free to play model, like many subscription MMOs are doing. But these statements by Blizzard developers allays those fears.