BioWare Mythic VP Eugene Evans stated yesterday in an interview with PCGamer that Warhammer Online is in fact not going the route of Free-to-Play stating,

Right now, we’re focused on [arena-based spin-off] Wrath of Heroes as our free-to-play offering in the Warhammer universe. We believe in the community of players who are playing Age of Reckoning. Yes, we could have attracted a lot of players to it [with free-to-play], but it’s unclear how long you’ll keep them. We wanted to support our game as it currently exists.

http://social.bioware.com/forum/1/topic/232/index/8501766/1