While adding the Elemental tag to additional minions might make you think about how it affects the odds of Servant of Kalimos - and it does by the way - there aren't really any other reasons most players would stop to think about what this change does. But Jade Spirit alone might be enough to make a significant difference in the power level of Elemental Shaman and pro players have been building and testing decks to prove it.
No one really cares about the fact that Mana Geode, Djinni of Zephyrs, and Hallazeal the Ascended now have the Elemental keyword. These cards are rarely used and adding the new tag is really just Blizzard's way of appeasing those looking for consistency.
To be fair, the fact that Jade Spirit has joined the race doesn't really affect the card itself, but it does do something else: vastly improve the curve of Elemental Shaman.
Look at the other 4-drops available to Shaman prior to this week's update. Fire Plume Phoenix is the only Elemental and it certainly isn't strong. Flamewreathed Faceless no longer sees play now that its Overload is too much to handle without the added benefit of Tunnel Trogg. The other powerful options, Jade Lightning and Jinyu Waterspeaker, are both somewhat reactive and playing them on Turn 4 isn't ideal.
This has always been one of the struggling points for Elemental Shaman which really wants to be able to play Servant of Kalimos on Turn 5. There have always been other ways to activate it's effect. Saving a Fire Fly or Hot Spring Guardian and sacrificing your earlier turns for a better midgame was somewhat common.
Most Shaman decks have already been playing Jade Spirit as part of their Jade core which also relies on cards like Jade Claws, Jade Lightning, and Aya Blackpaw. With these it's possible for the deck to have a really strong late game, a Jade Golem army pounding at the weakening gates.
But now the class has a single card that brings together the two halves of today's Midrange Shaman: Jade Golems and Elementals.
With this, the deck can now pivot more effectively. You can either go all in on a midrange build or add an Elemental flair to your Jade deck.
Pro players have been testing the waters to see if it's strong enough to stick around. A few, wiRer and Zanananan, made Legend with their deck lists. You can find them below.