Throwing knife headshots take a lot more practice and skill that a shoulder charge. Sure, if someone is looking directly at you in a long corridor, it's hard to get a shoulder charge kill, but it's a bad idea to try it in that circumstance anyway. Most of the time I'm killed from a shoulder charge its because of a titan running around a corner when I have no time to react. Throwing knives, however, and much harder to use. Gunslingers are all about precision, so precision throwing knives(not the explody knives or the three knives) should reward you if you are able to line up the shot correctly. Edit: most of the arguments I have been hearing are saying that it is "too easy" to hit throwing knife headshots. Fine. Make the hitbox smaller and turn off "aim assist" to make it much harder and much more rewarding.