You could play Feugen for the same cost.... who is 5 stats higher... yeah. I'm thinking it should've cost 4 but then again it might've been kind of strong if it did. I don't know. As it is, not viable at all.
I agree with Pilleri - dealing 4 damage on drop is pretty insane (think about removing Azure Drakes, or unhealed injured blademasters, or dealing with the pesky left-over sludge-belcher slime). I have the feeling this guy is going to be an under-rated champ.
I think this could definitely see play in constructed in a deck with decent CC. Against a board of 1 or 2 minions you should be able to kill something and then leave a decent body. I compare it to a 5 mana 3/3 Argent Commander if you can limit its targets to the one you want. Probably works best in some mid-rangey Shaman, Warrior, or Mage. Not a bad card at all.
I think we'll find this card fits in nicely into quite a few decks. He is going to rock mid-games. There are few mid-game cards that won't either die or setup an easy trade when it takes 4 damage. By trading before you play him you can more accurately get him to kill what you want dead.
Best of all, he's a neutral solution for (in my experience) the growing resurgence of miracle rogue. Turn 5, Auctioneer, prep, conceal. Respond with this bad boy to bust a hole in the rogue's plans.
He might very well wander into top Rare picks in Arena. He's essentially a Flamecannon strapped to a 3/3 body for 3 + 2 for the effect in question and while the battlecry is random, it's the kind of randomness you can control to an extent.
Not really a pick in Constructed unless for Randuins or specifically as an anti-Miracle Rogue tech card.
You can't say sludge is Sen'jin + Goldshire for 4+1 mana.
No, this is like 3/3 for 3 mana + draw a card which is flamecanon.
Not good enough in constructed: Not that it's bad, but there are too many 5 health-minions that it would trade favourably. Also this effect does nothing against zoo and other aggro-decks: a 3/3 is too easily destroyed, and the 4 attack might go pretty bad if it hits an egg. Against Miracle this card might shine; althrough the recent auctioneer-nerf might be enough to give miracle the execute ;-)
But wait and see: in current decks this card might not really shine, but i see many 3-4 health-minions with higher attack in the new cards.
I like playing him in my Druid deck (sorta Ramp), Ancient Healbot was also a choice, but i deceide to move over to the Bomber. And yep, it works fine for me (even in constructed), and to add some more rng to it, throw a Recombobulator in :) after he dealt his 4dmg. Had funny results like: Doomguard (which can immediately attack) .. its fun!
When/If this huge Mech Zoo meta calms down, this card will end up seeing a lot more play. This card crushes mid-range decks. But yeah, with everyone playing cheap-o Mech Zoo, there's no place for this yet.