When Blizzard released the Mists of Pandaria expansion, it instead focuses on the casual fans rather than those seeking more content for the end game. Despite upsetting the more dedicated user base, World of Warcraft lead designer, Tom Chilton, explained how Mists of Pandaria' helped the game reach its continued success.
When speaking to Polygon about the release of Pandaria, Tom Chilton said that Blizzard "would have been in bad shape had [they] not done that." The focus on the casual fans did take away from the more hardcore players, but Chilton acknowledges this issue. As the game reaches the release of the 5.4 patch to connect low population realms, Chilton promises to reveal the studios plans for hardcore players in the future.
Future plans may also include a free-to-play transition. Chilton admits that "for Blizzard it makes sense [to go free-to-play] at some point. But a lot of the risk is in making that transition." Despite the stories of games entering the free-to-play realm and doubling their user base, Chilton remains weary because of the possible drop off in players after that initial boom.
The most recent World of Warcraft update will aim to connect low population servers which may or may not relate to the huge loss of subscribers.
Source: Polygon