Hearthpwn

I think Conceal will be good after nerf Cold Blood.

I've found this deck being very good but i don't feel zilliax is synergic at all, what am i missing? Is it still the best choice no matter what?

zilliax plus a cold blood is a massive heal. that on it's own is sometimes vital. not to mention it can be used to stall as well and used as part of board clean up in tandem with other things for 5 damage (weapon, SI, the argent dude etc)

I'd say it's definitely great in the deck. 

If you wanted further synergy you could maybe try and add nightmare amalgam to the deck (I was looking at this myself) as it has both pirate and mech synergy, so you would have a target for zilliax, but it still has pirate synergy as well. (I think it's an odd cost card at least, I could be wrong. if so then scrap that. ha ha)

anyway zill is great in the deck. you could run dr. boom instead though I guess if you wanted. (or add boom as well for more synergy with zill? in that case you could try and add 2 x amalgam and boom and then have a mini mech tribe in there too. might be worth trying? the stats don't lie though, this is the best deck in wild at the moment for sheer winrate alone)

I crafted loathy boy.

it was the only card I immediately needed from naxx so was the best option for now. 

I'm aware that loatheb should be in greenskins place, I don't have the card yet though.

you might want to replace with an owl for silence.