I don't know how you feel about it, but technically, if an animal is able to leap great distances, then their bodies have to be strong enough to withstand the forces that exerts on them.
If they can attain any given height on their own power, then they can withstand the landing as well. Been working on my own Dragoon class (as it seems 9.9*10^n+1 people have done and are doing). That was one of the main issues I had with it. I just did away with the fall damage and mitigation. What good does it do to jump anyway when flight is so easily attained mid-game and you can't bull rush people off cliffs (because you have to end movement in a safe, empty square)?
EDIT: I also borrowed heavily from the ninja. I actually built a ninja that used a lance and asked the DM to make a couple of houserules to make the dragoon concept work, and that's where I started building from.
Good luck with your class design!