Knockdown rework (or new item idea)

[chaadbro]

Simple idea. Remove the stun, but keep the interrupt, and a movement lock while falling. Speed up the cast time, and add damage based on height.

I think this would make knockdown feel more threatening. Right now, if you don't have a cleanse for it, you can just position around it.

This could potentially allow for adding more vertical heroes and mechanics to the game as well.