The subtitle is a bit too small scope for a WoW expansion pack and fits with the teasers they've been dropping for Hearthstone.
The other obvious possibility is that this is the Naga expansion pack for WoW and they're referring to Queen Azshara and the Maelstrom instead of the goblin city in Azshara the region.
Source: http://www.hearthpwn.com/news/669-trademark-for-eye-of-azshara-spotted-possibleHearthpwn said:A trademark under Blizzard's name has been filed for Eye of Azshara in Benelux
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If you aren't familiar with World of Warcraft, Azshara is a Zone which sits in North Eastern Kalimdor, right above Orgrimmar. In the Cataclysm expansion, the zone was redesigned and with it came a large island in the center of the zone which was inhabited by the Goblins. It was called Bilgewater Harbor. This island sitting in the middle of the bay in Azshara resembles an eye when you look at it on the map.
The card back for November, titled Goblin, was released in the most recent client patch. That, along with the Blueprints which community members received in the mail, gave us a pretty good feeling that the next expansion was going to be mechanical themed. With the Eye of Azshara trademark showing up though, we could potentially see more Goblin influence in the cards instead of just generic engineering. Not only Goblins though, the Naga, Horde, and Night Elves also inhabit the zone in World of Warcraft, so there could be plenty of those too.
The other obvious possibility is that this is the Naga expansion pack for WoW and they're referring to Queen Azshara and the Maelstrom instead of the goblin city in Azshara the region.