Although many people (Shwoosh ;)) enjoy stickyjumping into people to crit them, all other random melee critical hits were removed to meet both sides halfway as a compromise. Critical hits have always been amazing to get, but annoying to be on the receiving side of, so it's particularly obnoxious when someone is rewarded for walking at you, mindlessly swinging their melee weapon. Taking triple the damage for no reason other than pure luck isn't fun.