Let's face the facts, WoW and GW2 are starting to get a little stale. Even with my admiration for the latter, I'm starting to getting frustrated with running dungeons over and over. The upcoming release of Elder Scrolls Online might ease some of the pain, but there is another title, a potential sleeper hit, that you may want to look into.
WildStar is an up-and-coming MMORPG project from Carbine Studios, a subsidiary of NCSOFT that was founded back in 2005 by former members of Blizzard Entertainment. WildStar will be the developer's first project, but consider that the team contains members that are probably very familiar with how MMO's operate.
The Sci-Fi themed title is aimed for a Spring 2014 release, so it's still a little ways off, but Carbine is giving eager/impatient gamers a chance to participate in a Winter Beta. With all of the hype surrounding this release it's a sure bet that the beta will fill up fast, so you'll want to be sure you get your application in as quickly as possible.
As of now, WildStar is set up to be a subscription-based title, much like WoW. However, with Guild Wars 2 having a successful non-subscription release, it will be interesting to see how gamers welcome another pay-as-you-play business model. Perhaps WildStar will change its pricing structure as it gets closer to launch, specifically with rival Elder Scrolls online gearing up to release sometime in 2014.