While Bonfire of the Damned is miles more efficient than Clan Defiance especially when cast for its miracle cost, the latter can be in your opening hand and it will be fine while the former is clunky particularly in multiples. With three mana, you can clear away a one-toughness blocker and ping an opponent for one. With more mana available, you can take out a nasty flyer like Restoration Angel AND a planeswalker. It's a nice answer to spells like Sphinx's Revelation and a way to kill planeswalkers without sacrificing a burn spell to clear out a blocker because now you can do both. This, in other words, is more than a pretty nice addition to the Gruul mage's toolbox.
I can see two to three copies of this maindeck with the rest in the sideboard. For my werewolves, I'd put in two at least as the ability to put away an opponent or remove a fattie is always golden. I wouldn't put in three or more unless Gruul gets a Birds of Paradise sort of creature as the RG in the mana cost can be restrictive in a werewolf deck.
So far, these are my notes on the card and I hope my readers can shed more light as to the uses for Clan Defiance in the days ahead.
