Playing against air blast in it's current state is really unfun.
If you try to uber into it, you just get indefinitely air blasted into a wall. Even if you manage to kill the Pyro while this is happening, by the time you have done so, you have wasted so much time to do it.
There should definitely be an increase in ammo required for air blast, so you can't just hold down right click for almost the entirety of the uber.
Additionally, knock back needs to be tweaked. If you are fighting a Pyro, you are immobilized by the air blast. You can't air strafe out of it, and it knocks back so far. You basically can't do anything aggression wise until the Pyro is dead. Taking that much movement away from the player is just unfun for the same reason Natasha is. If the knock back had less power and allowed the player to air strafe, it would be much better.