Even Shaman is a relatively new archetype that was enabled by The Witchwood expansion and the card Genn Greymane. This gives you the ability to use your hero power for just 1-mana, however, this isn’t the only benefit of going all even. Murkspark Eel, the Shaman class card, is extremely powerful and lets you gain tempo in the early game. This along with your cheap totems gives you the ability to continue to put many things on the board.
The Boomsday Project expansion brought along some interesting new tools for the archetype. Arcane Dynamo gives you a way to grab a spell that can suit your current predicament. Because it can only find Shaman spells, you have a high chance to grab a board clear like Volcano or a finisher like Bloodlust!