There are ways to build a slow and controlling hunter, especially in wild. More of a meme thing, than actually competitive, but it can be done. I could see Emeriss find a use in a board control hunter, one also playing Ysera for excample.
– The question then becomes do you hold Ysera to double her stats, or do you play her first so she can begin filling your hand with Emerald Drakes and Laughing Sisters.
– Of course you are going to play Deathstalker Rexxar as well.

I am not going to completely dismiss Emeriss, even though she is more of a fun card, than a useful card. I very much doubt she will see use in ladder at all, certainly not in standard ladder. Wild ladder? Not at the top.

I am pretty sure this effect will trigger after creatures have been put into a graveyard, since for the ability to proc reads “when it kills a minion” meaning after damage has been resolved. At least that is how I am reading it, I might be wrong.

If this is the case, then it’s pretty bad. If I am wrong however it’s an ok card.

At least Lorewalker Cho is fun.

At 4 cost its not even viable to pull of combos itself, though it is clearly meant for decks using either Gadgetzan Auctioneer or Combo cards, due to the coin.
– You will be using 4 mana, that might be all you get to do that turn, early on. Even if you remove a minion with it you are basically handing your opponent the turn in exchange for a coin..

If it had been common, perhaps this would have been acceptable, but as an epic with that cost and limitation, this might just rank amongst the worst epics ever. I would not spend 400 to craft this card.
– Had it been 3 cost, do 3 damage, minion or player, and gain a coin every time –
Like this? Worst rogue card in a long, long time.