Bit weak and situational for that huge cost, I'd say. Let's say you play four Cremations in one game (I usually don't get above 2 or 3), this would just not be worth the cost at all. Making it +3|+1 or +4|+1 and lowering the cost a bit might work. Fire -could- use a less fragile (at the start) creature, after all. I do see how it would be a good counter when it's fire vs. fire, though, which is a good idea.
