Hearthpwn

Well the problem with Mekgineer Thermaplugg is not the effect but his mana cost, a lot of people already say this, but it could be a 7/5 for 7 mana and it would improve the card by 3 times his value.

What I see on this card, is potential for playing it on some combo decks, consider this, some of the new cards so far give certain clases new possible playstyles, Mech rogue has already been discussed, following that logic the idea of playing Foe Reaper 4000 and follow with conceal is not that far from coming to reality, after all is like playing Doomsayer + Conceal and then getting a 6/9 in the board (Minus the damage that he would take from hitting an enemy minion to trigger the combo)

Other deck were I could see this card being played is in shaman being run instead of Al'Akir the Windlord in combination with Windfury or Windspeaker.

Also you mentioned Ramp Druid and also Handlock came to my mind, while Ragnaros is overall better than him in a Handlock deck I can see some people runing him in place of Loathed, after all with all the taunt enablers that handlock runs a card with 9 health looks very juicy.

Finally I want to say that people needs to remember that the game is "supposed" to be balanced for both constructed and Arena.

Quick! Someone post a picture of the artwork for this card and add "Do you even Harvest bro?!"

There should be a warrior card that is an 8/8 with taunt that cost 20 and 1 Less for each armor you have, then this card would be awesome.

- 1 Explosive Sheep           + 1 Tinkertown Technician - 1 Unstable Ghoul             + 1 Slam   - 1 Madder Bomber  

+ 1 Commanding Shout

Makes the deck more consistent, why would you have so many cards that deal damage to all minions when you have a lot of small and medium minions?