World of Warcraft "can’t really be revolutionary", says lead designer

World of Warcraft's user base is in decline partially because Blizzard can't afford to innovate, comments from lead designer Tom Chilton suggest.

Quizzed by PCGamesN on the subject of why World of Warcraft's players vase is down to 7 million - quite a drop from its peak of 12 million - Chilton had multiple answers.

"For one, the game has gotten older. We can only be evolutionary, we can’t really be revolutionary without betraying the existing playerbase," he said.

"It does limit how much we can change the gameplay experience to keep people engaged all the time."

The expectations of the hardcore player base also make it difficult for Blizzard to attract new players with expansions.

"If you imagine mapping our expansion model onto Call of Duty, and what kind of impact that would have," Chilton explained.

"What if when Call of Duty: Ghosts came out, it was only relevant to you if you had beaten [all the others]. You would imagine that the market for that game would decline. So we have to do a better job of getting people into the new content when we release a new expansion."

In the full article, Chilton touches on World of Warcraft's expanding microtransaction offerings, and the possibility of eventually going free-to-play.