Cue in medierra quote, circa 2010:
http://www.grimdawn.com/forums/showthread.php?p=5969#post5969
I don’t know if we’d actually allow this to happen to the player. It might be too annoying. If we did, I think it would have to be very limited and resists would certainly be in order. I think for enemies knockdown might be based on the % of their max life that you’re inflicting as damage using a skill that can cause knock-down.
As we can see, he decided that it would be too annoying.