How about a feat for Pathfinder? Who doesn’t love playing Mario with their enemies…
Death From Above
When you strike from above, you hit with devastating results
When you jump down on an enemy from a height of equal to or greater than twice the enemy’s height, increase your critical attack range by two. You can do this effect by jumping at the opponent instead of falling, but you must succeed on a jump check that results in you at least being twice as high as your opponent.