The problem is 95% of players are running a shotgun and you will take a shotgun shell to the face. Regardless of the damage it does, you're still going to die more times than you get a kill. The vast majority of kills are going to come against players that are in a gunfight with someone else. You would have killed them with your gun, anyway. To be honest, most of what you've said is extremely situational. You're not going to get a chance to knee someone in the face Nova Bombing or Fist of Havocing you 99.9% of the time.