Blizzard just announced there plans for the upcoming year in Hearthstone: The Year of the Mammoth is history and please welcome the Year of the Raven.
The new year will of course feature another three expansions (the first one launching probably early April), plus a set rotation, but also a lot more! 
New features
New Druid Hero! Lunara will join the game, free for everyone who is winning 10 games in the new year.
Quicker quests
The requirements for almost every quest will be reduced to make them faster to complete, and all 40 gold quests will now award 50 gold instead. Quests that awarded more than 50 gold will still have the same rewards, but with reduced requirements.New Hall of Fame cards
Ice Block, Molten Giant and Coldlight Oracle are all moving to the Hall of Fame set. You will get a full dust refund on each!An option for in-game tournaments
Starting as a beta in summer Hearthstone will finally feature an option to provide in-game tournaments. It will be relatively light on features for the start, but will expand further!
What do you think, good or bad news? The new set is getting announced in March, so keep an eye out!
That quicker quest update is massive change. When I was free to player back in the day, it was absolut pain trying to do some class quests with classes I didn't have cards for. I also have alot of times felt that some of the bigger gold quests simply costed just little too much time, and that made them frustrating.
Yes, I agree. The average expected value is going up to nearly 65g per day with this and some quests are just too long at the moment. I am happy that they finally include tournaments in the client, but it will be a long way until a fully functional mode I guess.