"What's the difference between AirBlast and Catapult? Catapult goes much higher!"
First of all, Catapult is the only real mobility move that earthbenders can use. Without it, they're basically stuck to the ground.
Secondly, AirBlast is a lot more powerful than Catapult because skilled users such as myself have developed a way to stay in the air until my mouse dies. Catapult can be used once and then you will shoot down and hit the ground unable to use it again for over a second. AirBlast on the other hand can be used over and over again with no cooldown whatsoever.
AirBenders have enough mobility as it is, they don't need AirBlast catapulting. I mean seriously, they can just jump in the air, move side to side IN THE AIR, it's literally impossible to kill them because the smart ones descend with AirShield active. As soon as they land and see that they have an open hit they just start AirSwiping and AirSweeping me. When they see an incoming attack, this same procedure takes place again.
Airbenders should not be kangaroo gods and we all know this, it is way too overpowered. The word "balanced" does not exist in a bending arena with an airbender so long as AirBlast Catapult still works.