World of Warcraft will remain the most successful subscription MMO ever released for many years to come, maybe forever. But the game’s popularity is waning, with well over a million players walking away this year already. That still leaves 7.7 million subscribers filling Blizzard’s coffers every month, but it’s nowhere near the peak of 12 million a few years ago.Blizzard isn’t ignoring the steady decline, and lead designer Tom Chilton has told Polygon that they intend to do something about it. He points to the Mists of Pandaria expansion as an example of how World of Warcraft is being opened up to more casual players, but also that future expansions are planned and there will be new challenges for the hardcore players.Whether a new experience for the hardcore MMO crowd will be enough to entice long-time players back is unknown. There’s a lot of alternatives out there now, and a growing number of free-to-play options, too. But that is one area where Blizzard may also react.Chilton has stated that it actually makes sense for World of Warcraft to embrace free-to-play eventually. The problem is, it’s risky and there’s no guarantee it would make the situation any better. Chilton acknowledges that other games that made the switch saw player numbers increase substantially, but he doesn’t have data on how long that boost lasted or how profitable it ended up being for the long term.For now, World of Warcraft will remain a subscription-based MMO with new expansions in the works to support hardcore players as well as continuing to embrace the casual market. Then one day it’s likely we’ll get a free-to-play version. But by then, we might all be focused on Titan, a game Blizzard has said probably won’t be a subscription MMO.