1:50 on that video was basically my thought after reading what this card does.
Why? Even if it does last long enough this power is too unpredictably situational. I mean I know there is a lot of situational to this game, but successful players prefer them to have some form of predictability.
*sigh* I hate it when what starts out as an assumption out of observations gets to be confirmed correct all along.
So some post testing thoughts now that in Un'goro is out so far in using it: The most prominent deck I think Dirty Rat has a place in, is believe it or not, the rogue quest deck and the results are quite amusing. Now one might wonder why its in there in the first place but rogues have the contingencies to handle dangerous minions with Vilespine Slayer and Envenom Weapon. All it takes is a good read on when to use it and quite honestly, Blizzard has made that easy with its use of indicators. It has ruined quests, sometimes through the immediate forcing out of their reward, and/or slowed them down to the point where i am able to complete mine over theirs. The best time i had using it in the deck is that it ruined a mage OTK by pulling out their important finisher cards only to be eaten up by vilespines so it has its uses if mage is relying on the one trick ponies that is Time Warp shenanigans.
I suspect his idea of value these days are the type of cards that allows him to do major things with the very least effort, meaning cards you just play and let the no frills magic happen. In fact I got the thought under these lines the best value card ever conceived would be a 1 mana legendary neutral spell with the effect "Wins the game". Oh! and it can be called the IWIN button, the legendary button because out of all the IWIN buttons it is one that didn't break.
....why didn't I come up with this before for April Fool's day? Then again i am no artist.
I'm starting to see this in several of my quest decks when theorycrafting......who said it had to be just for the warrior quest deck? It can be potentially quite the headache alone, and well his other taunt friend he gave you to throw up later, for any aggro decks since they mostly have to use every bit of damage they have on the face to succeed or then it becomes out of their control and if there's no threat of aggro then its discover can cycle itself out for a card that could aid the quest or is just plain better while still being a bit of a presence.
Deathrattle cards sounds like something that doesn't fit well because rogues would preferably want to bounce re-summon battlecry minions, but considering the 1 mana 1/2s that are useful for and after the quest I'd consider this an exception.