Well, I still think upped Gargoyle is stronger than this.
I mean, look at the cards:
Gargoyle: 1 more quanta for 7 flat attack, and 3 less health (but possibly like 17 more health on the next turn...)
Harpy: 1 less quanta for up to 7 attack; 8 with Nightmere only, and that's ok it's possibly the whole point of this card. But the health advantage is (almost) meaningless, and normally this card would have less attack than a Gargoyle, possibly even 0.
I think this is kind of weak, I'd say at least 1+X attack on the upped might be in order...