It sounds like Blizzard is planning to make a big splash at PAX East in March: The first day includes a panel featuring Dustin Browder, Eric Dodds, and Jeff Kaplan talking about what's coming to Heroes of the Storm, Hearthstone, and Overwatch in 2015.
Blizzard hasn't dropped anything specific in terms of what it's got cooking, but the description of Friday's "Blizzard Preview" panel is clear enough: "Bold new heroes, exciting new cards, and epic new battlegrounds," it states. "Join a trio of Blizzard Entertainment developers for a look at just some of what’s in store for 2015, including upcoming content for Heroes of the Storm, Hearthstone: Heroes of Warcraft, and Overwatch."
It's a good bet that Blizzard wouldn't trot out Browder, Dodds, and Kaplan—respectively, the game directors on Heroes of the Storm, Hearthstone, and Overwatch—unless they had something of substance to say. Let us also recall, as noted by The Daily Dot, that the Hearthstone single-player adventure Curse of Naxxramas was announced at PAX East last year, and that Hearthstone itself was revealed at PAX East 2013. Clearly, Blizzard isn't shy about dropping big news in Beantown.
This year's edition of PAX East runs from March 6-8, and we'll be there in force. While you wait, feel free to spend some time with our recent interview with Browder about the future of Heroes of the Storm in which he said we "haven't seen anything yet," and also our December chat with Hearthstone Senior Game Designer Ben Brode and Art Director Ben Thompson, who held forth on topics including card balance, deck slots, and what the hell use Flame Leviathan is to anyone.