2017 Is Hearthstone's Year of the Mammoth: 3 New Expansions, 6 Cards Removed From Standard

Here's the good news: Instead of simply allowing players to convert these cards into Arcane Dust for their full values -- as has been done in the past with cards that were similarly restricted or altered -- Blizzard will award players the Dust value of those cards and let you keep them in your collection, so you can use them in your Wild decks. This is limited to a number of cards equal to how many you could put in a deck -- so one for the legendaries and two for the other cards. It also means that if you don't have some of these cards, but do have the Dust to craft them, you should do so before the first expansion of the year releases. You'll get your dust refunded and you'll get to keep the (essentially free) card.

What else is there to know? Heroic Tavern Brawl will return, and there will be more third-party tournaments using the Wild format. Prior to the expansion, Blizzard will introduce daily login rewards "as well as a few other surprises." Finally, after the expansion goes live, you can earn a new rogue hero, Maiev Shadowsong, by winning 10 games in Standard Casual or Ranked play.

It's a lot to absorb, so make sure to read through the entire post on the Hearthstone site.