The next Hearthstone expansion is Titans, set in the distant past in the city of Ulduar, which stands above the imprisoned Yogg-Saron.
A pretty substantial balance patch is hitting the Hearthstone servers today, promising to make things more balanced in Constructed and Battlegrounds.
Hearthstone is getting a new card type for the first time in five years, and only for the second time in the game's history. Location cards are arriving with the Murder at Castle Natrhia expansion: cards that represent specific places from the world.
There's been a Murder at Castle Nathria, and Sire Denathrius is dead!