Lions and tigers and wolves, oh my?
Man, I keep seeing cards that would go great with that Gift idea someone had a while back. This triggers off stuff like Fire Shield, right? Give your opponent a damaging shield, pack a couple Archangels and Lions, and maybe bless a couple Voodoo Dolls. I don't remember what element Gift was, though, that could end up being a quartet. Would creature poison trigger the damage? If so, you could run Parasites, Voodoo Dolls, and Lions for some pretty crazy stacking. Holy Light would be boosted to 12 damage a pop.
This is powerful, but I don't think it's too much. Rush decks wouldn't be affected at all, any deck with healing is going to be able to plan a bit and make up for the extra damage, and as for Rain of Fire or such... multiple Vultures already do something like that, and without your opponent handing it to you. I don't know about Procrastination, but Permafrost freezes stuff for long enough that the shield's effect is still better than letting enemy creatures run free (plus it's blocking 2 damage on top).
Great card, all kinds of interesting combos. An example of why I say simple cards are usually better.