I don't think it's outright bad. It provides imediate 5 damage in a class that likes to race, it goes wide without being all that susceptible to aoe, and with a taunt that protects it. However, would you really play this in anything but midrange, how much does an 8 drop need to do, and is it better than Ragnaros? The most annoying part of it is that it totally whiffs with the Elekk. Ultimately, I expect it to be a budget 1-of for midrange, and nothing else.
I'd say it's significantly better than Ragnaros. You're getting 22 points of raw stats, plus 5 charge damage, taunt and a boardwide buff for a very aggressive price. Furthermore, it's a pretty resilient combo: there are precious few ways (especially in Standard) to answer it and still come ahead. You can't neatly BGH, silence or Hex the entire trio, and AoE options that can nail all three are very expensive and/or kill your own board as well.
What's more, CotW is like Dr. Boom in the sense that it's almost never a wrong decision to play it. If you're behind, it's a great comeback mechanic. If you're tied or ahead, you instantly cement a backbreaking advantage. Yet unlike the good Doctor, you can play TWO - and, unlike Mysterious Challenger, the second one will be just as effective as the first one.
Yes, Face Hunter won't run it, but that's OK: Aggro Paladin decks based on Divine Favor didn't run Tirion, but that didn't make the latter any less ridiculous in other Paladin decks.