The ones announced today Hearthstone Balance changes target several dominant deck types, including Warlocks, Paladins, and the Wild Format Naga Deck.
Hearthstone card changes
The first change concerns the Wild Format in which decks dealing with multiple giants and the Naga Sea Witch became quite rampant. Depending on the course of the game, you could already play 3-4 giants in turn 5 and stopping such a superiority was almost impossible.
Even before the Hexenwald expansion, there was the Big Spell Priest who only had 4 spells with 8 or 10 mana costs in the deck and thus used the wicked summoner. There are now a number of other classes such as Druids with Unholy Infestion that use the card.
Since there are now less than 10 mana servants in the standard format and the effect was significantly stronger, Blizzard increased the mana cost to 7.
One of the dominant decks right now is the Demon warlocks, who with Skull of the Man'ri and the possessed lackey could already come up with Doomguards and Void Lords in rounds 5-6.
The combination of Obsessed Lackey and Dark Pact will now be somewhat defused. The pact only restores 4 instead of 8 lives. The footman's mana cost increases to 6.
Anyone who does not play a sorcerer in the ranking is sure to play paladin meanwhile. The paladin decks are extremely powerful and diverse right now. Whether it's Baku with odd cards or Genn decks with even cards, both are very hard to beat.
Blizzard still shies away from stronger weaknesses, but at least off into battle will be unusable for even decks due to the mana cost change from 4 to 5 mana.
The card is therefore also relatively useless for odd decks, since these decks cannot have servants with 2 mana.
The final change concerns Quest villains, Crystal Core turns your creatures into 4/4 servants instead of 5/5 as before.
According to Hearthstone developers, Quest villains were too strong against fast and slow decks alike.
The planned changes will come with the Hearthstone update after the HCT playoffs.