Pretty much. Mysterious Challenger is 6 mana, but you get about 20 mana of value out of him if he plays the full tree. How did I come up with 20 mana? First, he's a 6/6, that's essentially vanilla 6 cost minion. Boulderfist Ogre is better, but it still passes the test of health + attack = cost * 2. But then he draws 5 cards. The formula for card draw cost in the past has been # cards drawn * 2 - 1. Arcane Intellect: 2 cards, 3 mana. 2 * 2 - 1 = 3. Nourish: 3 cards, 5 mana. 3 * 2 - 1 = 5. Sprint: 4 cards, 7 mana. 4 * 2 - 1 = 7. There are some exceptions to this rule, but most don't stray too far. But Mysterious Challenger totally fucking ignores it. 5 cards, 6 mana. 5 * 2 - 1 = 9. The card draw aspect alone of MC is undercosted by 3 mana and that's without the body. So, we're up to 15 mana value for MC, but then he plays the god damn secrets for free, another 5 mana worth of value. So we have a 6 mana body, 9 mana worth of card draw, and 5 mana in cost reduction = 20 total mana for the cost of 6.
This is a terrible way to evaluate cards. Is Sludge Belcher a 5 mana Tazdingo that
draws a Goldshire Footman, and then plays it for free? Would anybody play Sludge Belcher if it costed 7-8 mana? Is Dr. Boom a War Golem that
draws two boom bots and plays them for free? Is Dr. Boom a 12 mana card? Not no but heck no. And before you say "oh these effects are different because they don't draw cards" you're right, they're actually
better than that because you aren't forced to include those extra effects as cards in your deck. They're generated for free.
You have to understand that effects like Arcane Intellect or Sprint and the act of putting
specific cards into play are costed very differently because they do very different things and accomplish different goals. There is an instrinsic value in holding a card in your hand, and the draw factors in MC dont do this. So the mana cost of "drawing" the secrets itself is actually quite small, if negligible.
The correct way to evaluate Mysterious Challenger is to add up the mana cost of all its effects, based on their relative power, We know that Avenge and Repentance are both 1 mana cards but Avenge is at least twice of good as a card as Repentance. So we take that into account. And then maybe knock off a bit of cost as a "penalty" of being forced into placing cards in your deck.
So 6/6 body. This is effectively 5.5 mana worth of value, putting it between Pit Fighter and Boulderfist Ogre. Avenge and Noble Sacrifice are both solid 1 mana cards. This is why people always put 2x of both into their Secret Pally decks. Redemption and Competitive Spirit are both okay cards on their own but definitely weaker, so I'd cost them around 0.75 mana each. And Repentance is a pretty bad card which I'd evaluate at 0.5 mana or maybe even less.
Sooo.... 5.5 + 1 + 1 + 0.75 + 0.75 + 0.5 = 9.5 mana
Next we might want to consider our "deck building" penalty. Now If you still think I'm crazy for considering this, think about how much more powerful Secret Paladin would be if you didn't have to include the secrets and you could just slide him right into Midrange Paladin.
So this one is a little harder to quantify, but consider that we really hate to include Redemption, Competitive Spirit, and Repentance in our decks. I think most people have resorted to only include one-of on each at this point. And then consider that if we play a second one our value is cut pretty significantly, especially if we drew our secrets earlier in the game (which we probably did, let's be honest)
I'm going to put the penalty at about 1.5 mana, since that's pretty close to the value we shaved off of Redemption, Competitive Spirit, and Repentance, plus a little extra for taking into consideration how much weaker our second MC will be.
Puts us at about an
8 mana card. Isn't that a bit closer to what people perceive his actual power to be? Isn't that why making his stats 4/4 a pretty common suggestion since it takes about 2 mana worth of stats off of him? Not some
20 mana nonsense?
I mean 8 mana is still abso-fucking-lutely ridiculous. That means he's got a 2 mana worth of OP in him, which is huge. That's a 4 mana boulderfist ogre. That's a 6 mana Ragnaros. It still puts him ahead of Dr. Boom, who has about 1-to-1.5 mana of OP in him. Card is broke, but he isn't
20 mana broke.