actually, it should be a substitute for magical flight. why should fighters have to depend on casters to get them into the air? that's one of the fundamental imbalances of the system, in that martial characters are dependent on either casters or gear created by casters to contribute to a variety of encounters that those same casters can solve with a single action. anything that reduces magic dependency is a good thing.
@dragons. if they aren't flapping, they're gliding. to glide, they have to hold their wings straight to catch the air. making wing attacks while flying would only work as part of the flapping motion, the same as making attacks with the ax while spinning it.
dragon: dips its wing a bit to hit someone with the flap.
orc: tilts a bit to chop with the axe blade. or drops a couple of feet to spin parallel to their head, or whatever.
they maintain the spin while attacking, just like the dragon would have to maintain the flap while attacking.