"We've seen a significant number of people, well over half, that cited Warhammer as their reason for leaving--they've already returned." Blizzard COO Paul Sams told GamesIndustry.biz. "It surprises me because Mythic is a very good company and it doesn't surprise me at the same time because it's really hard [to make an MMO]."

"I think Warhammer is best positioned to succeed out of the various products that have come out thus far since World of Warcraft has come out," he explained. "It seems to be a good game, certainly a great company, Mythic and Mark [Jacobs] over there and his team, they're very, very talented."

"We respect those guys over there a lot and certainly wish them well to succeed but having registration troubles, having server troubles, these are things that come with the territory."

Since its September 18 debut, Warhammer Online has amassed over 750,000 players. World of Warcraft, launched back in 2004, currently has 10.9 million subscribers, with a new expansion pack, Wrath of the Lich King, due out November 13.

"Each time an MMO has come out we've seen some amount of reduction of use," Sams noted, adding that the company saw a drop when Funcom's Age of Conan launched back in March. About 40% of those that left for Age of Conan had returned by July, according to Blizzard CEO Mike Morhaime.