Hearthstone changes hit many of the most popular classic cards

Blizzard has announced changes to some of Hearthstone's most popular classic cards.

The rebalancing comes ahead of next week's new expansion, Whispers of the Old Gods, and is designed to ensure the new cards have a greater impact.

Hearthstone's Druid class has taken the greatest hit by far: three of its most popular cards have been neutered.

The deadly Force of Nature which summons three 2/2 Treants with charge - meaning they can attack immediately - has had the charge portion removed, although the Treants will remain after the end of your play. The card now costs one mana less, but the changes mean its powerful combo potential is now gone.

Other changes have hit fellow Druid cards Ancient of Lore (seven cost, with the potential for two card draw - now just one) and Keeper of the Grove (four cost, with the potential to do damage or silence a minion - now with its health cut in half).

Non-Druid changes centre around the ability to Silence or completely remove minions. Ironbeak Owl becomes a three-cost card, up from two. Big Game Hunter is now a five-cost card, up from three. And the Hunter card Hunter's Mark now costs one mana, up from zero.

Finally, Blizzard has nerfed a handful of cards used frequently in a majority of decks - to keep these from dominating play, it has said.

Knife Juggler and Leper Gnome have had their attack strength reduced, while Arcane Golem's charge ability has been removed - effectively killing off its main use. Molten Giant will also now take longer to summon.

Next week also sees the arrival of the new Standard format, which will limit the game's active card pool to the last two years of additions only. In other words, Goblins vs. Gnomes and Curse of Naxxramas are out - although a separate Wild mode will still allow for matches with all cards available.

Blizzard's argument for all these changes is that it wants to keep the game fresh. This is undeniably the case, although the dual tasks of continually releasing popular expansions without overpowering the game will also be a factor.