While I had fun playing with and against these decks, Wizards correctly realized that people enjoy the game a lot more when they get to do stuff like play creatures and beat down. Being completely shut out isn't fun. Losing to an opponent who plays better creatures isn't the most fun, but it is infinitely better than losing to an opponent who never let you play your game at all.
Magic changed for the better to make that happen, and Hearthstone seems to be doing the same thing with the new Whispers expansion. Check out the newest Legendary card to be revealed, N'zoth the Corruptor.
The reason this matters is that control decks in Hearthstone have been aiming for long games, often being designed to win by simply running the opponent completely out of cards. Elise Starseeker has accelerated this trend, setting up a game style where you don't try to win at all until the last couple turns when both decks are already empty. That is a long time to play, especially if you are the aggressive deck and you knew you lost ten turns ago but kept playing out of a faint hope of a disconnect or outrageous luck.
These new cards in Whispers of the Old Gods enforce a new kind of control. That new kind of control tries to stay in the game until turn 10 and then do something absolutely outrageous to blow the opponent out. These new 10 mana cards are worthy of the cost, which has not been true of most 10 drops in the past. This new kind of control isn't going to be playing nothing but removal, and it isn't aiming for fatigue. It is going to be playing minions, brawling for board control, and doing lots of trading.
And that stuff is FUN. People like playing minions and bashing them into each other. That is just plain old fun and is the core of Hearthstone, much as it was the core of the joy of Magic.
There is plenty of strategic depth in playing hard control with nothing but removal. You do need to think, plan, and consider. No question on that. However, the masses of people really do enjoy monsters brawling each other, and this new soft control style will do plenty of that.
Not that every hard control deck will go away, mind you, but I think they will have huge difficulties fighting the new soft control decks. Sure, you can load up on nothing but removal and keep your opponent's board clear, but how will you deal with the turn 10 that hits you for 20 to the face, summons a complete set of 7 monsters, or does whatever else the remaining 2 Old God cards will do? How do you prepare for all of those eventualities, while still keeping yourself secure against hyper aggro decks and midrange?
I think the answer is that you won't be able to have enough answers for all those things. Pure control, hard control, of the kind that just sits there waiting for fatigue, will get squeezed out. Soft control decks that play enough healing, taunts, and removal to fight for the board will be the new big thing, but they will be playing tons of minions too. Whether those minions are cultist types like C'thun decks will have, deathrattles for N'Zoth, or something else entirely, they will be out there on the field of battle duking it out.
None of this is accidental. Blizzard wants to build a game that is fun for newbies, and getting beaten by control warrior on turn 25 isn't as much fun as throwing down dorks, brawling, and then dying to something absolutely spectacular on turn 10. Especially so because then you can go and get your own turn 10 monsters and blow other people out too. While the Old Gods are part of a theme, I am confident that this theme and the way it affects the metagame is deliberate and designed to do exactly what I am describing. The game plays best when it is resolved somewhere between turn 8 and 12, and a combination of aggressive decks trying to close things out early and control decks playing 10 cost monstrosities is exactly the ticket to getting there.