Hearthpwn

I agree with a lot of your comments. My most recent variant (not posted) includes one Sprint and less combo minions like SI:7 Agent in place of more solid ones like Anub'ar Ambusher. My current experience suggests that dealing with enemy minions with bulky minions instead of spells and battlecries/combos works best since there is no good way for the class to remove multiple mid-late game minions without board presence. This is helped by the class being given lots of chunky minions since Naxx. 

On the point of Anub'arak, it is actually quite effective and certainly very satisfying. Other big legendaries would work better in the instances you are only able to play it once, but you may need one or two more of them to compensate for them not coming back. This would have the benefit of being more likely to have drawn a big threat when you need it, but limits options for other parts of the deck. In short, he's not essential, but the deck structure might need shifting to be slightly heavier if you want the same impact against slow decks.

The deck and its variants are still very much in the testing phase, and I personally try to avoid using super powerful minions like Piloted Shredder because I don't enjoy them much, so I recommend you try out other cards as there's a good chance they improve the deck a bit.

Quote from z3rO1 jump

If you don't waste cards just to make him bigger, having a 3-mana minion eat a silence/BGH isn't a major problem

The usual Backstab Knife Juggler->Coin->Edwin IS a huge waste if he gets silenced. And he just became a 6/6 vanila.
Instead you could dagger up and Deadly poison. Or you could Coin->SI:7. Both plays are better than getting a 2/2 for 3.

Agreed. I meant that if you play him as though he was just a vanilla 3-mana minion when it happened to fit the mana, instead of going out of your way to make him the focus of the turn, then the problem is reduced somewhat. That is, I personally find him best played almost by accident, just because he fits the mana and happens to be a 6/6 for 3.  

If a coin from Cutpurse helps out with making him fit, then that's no bad thing

Quote from z3rO1 jump

What about Edwin VanCleef?

Hey, if people suddenly start cutting owls from their decks for whatever reason, that guy will become good. 
Because the reason you don't play him is because he will either get BGH'ed or Silenced, and if you can dodge the BGH, you can't dodge the silence. Making him into a 6/6 only to eat a silence is just a waste.

If you don't waste cards just to make him bigger, having a 3-mana minion eat a silence/BGH isn't a major problem

The card has so far been really good in control decks with lists a bit like this 

Obviously some cards are not optimal, but it provides enough time for Beneath the Grounds to work without forcing your opponent to draw.