Let me begin by saying that this deck performs very well in the current meta, with positive or balanced matchups against all Hunter archetypes, Control Priest, Even and Odd Paladin, Odd Rogue and Even Shaman. It does worse against Resurrect Priest, Exodia Paladin and Odd Quest Warrior, although it does decently against Odd Dragon Warrior.
IBook of Specters has been used by Brian Kibler as the basis for his Elemental midrange deck, and it’s been used for other minion-heavy decks (obviously) like Murloc Mage. However, there wasn’t enough “meat” to these game plans- they suffered against board wipes, were out-tempo’d by the likes of Odd Paladin, and generally didn’t have enough tools to sustain. We received three of such tools in the latest expansion- Firetree Witchdoctor, Arcanosaur and Crowd Roaster. The inclusion of these cards into the Elemental Book of Specters shell turns it into somewhat of a proactive control play style.
The aim is to control the board with a vengeance. Your early game is very limited, so Fire Fly and Witchdoctor in your opening hand can sometimes make a huge difference down the line. Once you get into Turn 4 and on, many of the battlecries make an immediate impact on the board, such as Fire Plume Phoenix, Scaleworm, Zilliax, Blazecaller and Crowd Roaster. Clunky value trades are inevitable, which may feel bad at first, but each turn that ends with you having more (and bigger) minions on the board than your opponent creates insane pressure for them.
Deciding when to switch to pushing face damage can be tricky. Against aggro decks, I’m generally meticulous about board control until their resources have been all but depleted. This means taking unfavorable value trades more often than you would like to set up for the lethal turn down the line. Against control and combo decks, you of course will be pushing face damage much sooner.
A word on Arcanosaur: yes, it’s Duskbreaker for two more mana. However, Duskbreaker’s power level is so insanely high that I argue it would still see some play at 6 mana, and in terms of the current meta, you rather have an answer to the Spellstone on curve in this deck than not.