The minute I saw Spirit Echo during the Un'goro prerelease, I knew I wanted to make this deck. The idea is very simple: mill your opponent like a Rogue. Except, instead of using Shadowstep and Gang Up, you're relying on Youthful Brewmaster and Spirit Echo.
This is obviously slower because Shadowstep is 0 mana and lowers the cost by two, whereas Youthful Brewmaster costs 2. However, Youthful also puts a minion on the board. Also, Spirit Echo hits your whole board. This deck takes advantage of that by loading up with minions with healing battlecries to help you survive the game, such as Jinyu Waterspeaker, and Thing From Below, which can turn into a 0 cost 5/5 with taunt if you keep hitting that totem hero power.
Ideally you want to summon totems as quickly as possible to get your Thing from Below to 0 mana. Then, drop a Coldlight Oracle and Thing from Below, and hit Spirit Echo. That'll get another Cold Light in your hand, plus another 0-mana Thing. Nice! Sometimes you can pop a heal battlecry back to your hand, too.
Your best mass clear in this deck is Volcano, which you want to use early. I never hesitate to sacrifice minions to clear the opponent's board, because your Volcano is going to clean up and there's no sense wasting its hits on your own guys. The Curator is there to pull your Coldlight and provide another taunt.
Save Earth Shock and Hex for nasty combos and big minions, respectively. Try to hold back cards and maintain a clear board with minions and totems.
Possible techs: Harrison Jones, Prince Malchezar (if you find yourself running out of cards too soon), Daring Reporter, Forked Lightning (great early game vs. all the midrange out right now), Lightning Storm, Flametongue Totem, you know the drill.