Hearthpwn

++Update: It seems, this deck will get a solid buff. In the upcoming Patch Mountain Giant will get an Elemental-Tag, which will of course give this deck an additional synergy-factor++

So this is a Guide for Mage-Fans such as myself.
Concerning the Meta, I've heard so much about this being a real Midrange-Meta and even though Big Spell Mage is not a bad deck atm (with so many different lists and interesting twists) I sometimes had the feeling that it's Board Wipes wouldn't be as necessary or effective even. You could even say, these Big Spells aren't even countering certain Decks in the current Meta but are hindering you from building up your own Board and forcing you to rely on the Death Knight too much.

So I stumbled upon Kibler's Elemental Mage as a Midrange Deck, doing great against various Decks.
I've basically seen every Video on YouTube, uploaded and played by Brian Kibler. So first of all, here is a Video from OmniStone, where he presents and explains his list himself:

The deck's concept besides being a midrange deck is having a full hand throughout nearly the whole game, filled with board-centric options and beefy minions.
The strongest part of course is Book of Specters which the deck is built around.
In combination with this, there are so many cards that generate more ammunition such as Fire Fly, Bonfire Elemental, Lesser Ruby Spellstone, Pyros and many more. Book of Specters on Turn 2 not only allows a Turn 4 Mountain Giant (Turn 3 even if you start with the coin), he stays a 3-5 Mana Card throughout the whole game.
Cards that not only draw us more cards but generate cards outside of our deck also have great synergy with Leyline Manipulator.

Concerning different card choices:

Glacial Shard
Glacial Shard has proven to be a great and underrated choice, as it allows us against decks like Greymane-Lock or any Spiteful-Decks to build up a board as an answer to a Mountain Giant or a buffed Hooked Reaver.
Besides playing Frostlich Jaina on Turn 10+, freezing a threat as well as keeping up the elemental synergy for the upcoming turn makes playing Jaina much easier and threatening.
It can also be recycled into a 3-Mana Water Elemental with Jaina's Hero Power.

Servant of Kalimos
Playing this deck the first few games I realized, with a hand filled with options, Servant of Kalimos had always been the last choice. It doesn't make much sense, since a 5-Mana 4/5 is not that bad of a play, especially with the Leyline Manipulator synergy going forward, but there was never a great time to play this card. The elementals you could discover did never make a great difference, since the only choice you pretty much always want is Blazecaller. In conclusion: There are too many elementals that do not make a difference in a midrange race that justify a 5-Mana 4/5.

Baron Geddon
I had always perceived Baron Geddon as a Reno Jackson kind of a guy in combination with Jaina. But in this deck, you rarely play it for it's life gain purpose, but rather because any boardwipe-ish effect in a minion-based deck is pretty important. Especially in Matchups like Baku-Paladin or Midrange-Hand-Druids. As a more defensive card with same purpose, you could switch it for a Primordial Drake, but you'd be loosing the life gain option and elemental synergy.
If your Matchups allow it, you could switch it for a Water Elemental or Steam Surger for being able to play beefy minions earlier in the game.

Archmage Arugal
Kibler tried Arugal in the first lists of this deck, but it always turned out to be overkill and just adding more Minions that generate more cards themselves worked out quite nicely.

Polymorph
With the addition of Mountain Giant, you really want to pull off the successful turn 2 Book of Specters as consistent as possible, which is why Polymorph did not survive this version of the deck.
In addition to this, being able to pressure slower decks is more important in general.

When i have earned more experience with the deck, i could add matchup guides, if there is enough demand.
Please let me know, how you would change this deck and what your opinion on this deck is and of course watch as many Videos of Kibler playing this deck, because he explains many cards and choices pretty convincingly, in my opinion.