The inspiration from this deck comes from Garra's Dreamhack Warlock deck and marijuana.(deck here: http://www.hearthpwn.com/decks/48045-dreamhack-bucharest-2014-gaaras-nr-1-w1)
I was testing out the deck and made a bunch of changes because of the Druid in the meta-game when I was surprised at how well the deck flows. I didn't feel like blood knight was reliable enough for me because it either made you skip your argent squire to get the 6/6 blood knight early in the game or play it and not be able to get the 6/6. I cut out the divine shield element and decided to play Void Terrors. I then realized how well a lot of the cards synergized and built the deck around a few combinations. I'll list them down below:
Power Overwhelming+Shadowflame(preferably on the watchers)=instant board clear
Power Overwhelming+Ironbeak Owl=minion doesn't die. It can also heal the minion as well
Power Overwhelming+Void Terror=big ass void terror and you would lose the minion anyways
Flame Imp+Molten Giant=Molten Giant 2 less mana
Ancient Watcher+Ironbeak Owl=aww yeah
Ancient Watcher+Void Terror=helll yeah
Leeroy Jenkins+Power Overwhelming=gg
Everything else seems pretty much standard stuff. Here are some things to keep in mind:
Use your Molten Giant's before Jarraxxus. This is because Jarraxxus starts out at 15 health instead of 30, meaning that he will never be free to use after you play Jarraxxus.
Save your Siphon Soul for something important. It's only 1 of 3 cards that can heal in this deck and wasting it on a Cairne doesn't seem smart to me.
I feel that everything is necessary in this deck in my opinion. Having 2 Owl's, Void Terrors, Power Overwhelmings, etc. have such great synergy with each other that I have a hard time cutting anything. I also want this to be strong in the early game so I made sure to have enough early minions. I may just have some tunnel vision so feel free to adapt it and get back to me.
Matchups: In my opinion this doesn't really have any "bad" matchups but there are some situations that you get unlucky with your cards and your opponent has all the right cards. I don't want to spread false information because I haven't played this deck for an extended period of time but feel free to ask about matchups in the comments and I'll try to help.
edit: this seems to get rolled by face hunter(good nerf timing though blizz) and I've been crushing handlock