Ah. Gotcha.
One idea to make it a little more distinct from the dragon would be to drop the attack a bit and use the extra line to allow the ability to be multi-use. E.g.
"
: Sacrifice a permanent.
Can be used 2 times per turn."
That way you could drop it to something like 1 or 2 attack. It would keep its damage on par with dragon, but would promote it more for use with buff spell combos.
Right now, it will probably overshadow the dragon as it has roughly equal stat efficiency and an even higher damage output potential due to its abilities.
At any rate, I do really like the concept. It serves a unique niche with permanent destruction. Both as a deterrent to the opponent and as a potential combo-core for pulvy or SoFo decks.