I've been playing around a bit with Secret Paladin. After playing a bunch of games against it and a bunch of games with it I feel pretty comfortable saying that it's OP as fuck. Shielded Minibot single handily gave Paladins one of the best early games. Especially when you combine it with other other sticky minions. Going any combination of Shielded Minibot, Haunted Creeper, Mustard For Battle (I like French's) and/or Coghammer into a Turn 4 Piloted Shredder gives them a board presence that is really tough to crack open. Then once turn 6 comes around (or turn 5 + Coin) and you can drop Mysterious Challenger the game can just be blown wide open. At that point your deck is so thin that you're likely to only draw good stuff from there on out.
MC is getting a ton of coverage lately. Reddit is up in arms over him and that's spilling onto the main forums. I saw Krip's video too where he took results from people botting and found that a Secret Paladin deck was still able to win over 50% of the time when all other classes were below 50. That's pretty telling and it's pretty accurate. There isn't a lot of thought into the deck. You simply play your strongest cards each turn. It plays itself. Rarely do you have to decide on trades because your opponent is, rightfully, scared to death of a Secret Christmas Tree lighting up or a Quartermaster coming down to buff an army of weenies (even if most Paladins don't play QM right now it's something people have been conditioned to fear just in case he's there after a Mustard).
I got to live the dream against a Priest. Turn 2 Shielded Minibot, Turn 3 Coghammer, Turn 4 Piloted Shredder, Turn 5 Juggler + Mustard, Turn 6 Challenger. At that point my hand was empty but he couldn't dump his fast enough so I Divine Favored for 6 cards. His 5/10 Taunt was simply a speed bump on my way to his face.