Where Shamans rise, Hunters fall. Both Shaman archetypes are a strong counter to Hunters, and this has resulted in a drop in its numbers. At legend ranks, people are shying away from the class for the same reason: its not a fun matchup for the Hunter.
While the number of Warriors slightly dropped, the class is quite well positioned in the Meta. Control Warrior is the most common control archetype in the game, and its numbers are significant at the highest level of play, where Hunters are not as common.
Mid-Range Shaman has launched itself to the very top of the Power Rankings, and were not surprised. This archetype has meteorically risen in its performance against the field after Karazhans release. Its capability of beating Aggro Shaman has resulted in a massive internal shift within the class. With Shaman now possessing the two statistically strongest decks in the game, were waiting to see if theres any class that can unseat it from its throne.
The class that might match up best against Shaman is Warrior. While Control Warrior has a modest overall power ranking, its a stronger deck at the highest levels, and its capable of beating both Shaman archetypes consistently, though Mid-Range Shaman builds that are greedier might pose a bigger challenge to it. Dragon Warrior is also a well-established counter to Shaman, being able to beat it off the board in the early game and snowball from there. We think Warrior has a good chance of rising in its popularity, especially if Hunter continues to drop in numbers.