If you play DoC exactly on 5 (or 4 with coin) without drawing any key cards first, then yes, it's awesome. If you don't though, you just play a bad deck. So yeah... no.
In my opinion, this card could work for like 2-3 mana, because then you could play it in regular Control Lock as an additional win condition, aiming to buff 7-10 minions from your deck, that you would play anyway, even without DoC. You managed to pull it off? Good for you. You didn't? Shame, but you still have a good, viable deck, so no big deal. For 4-5 mana it's still too terrible.