RPG back blast dealing damage to enemies and teammates. This would add yet another layer of tactics to the engineer class, and would add another trick that would be so cool to pull off. Just imagine sneak up behind an enemy, pulling you out your rocket launcher, turning around, and killing him without even looking at him. Now that, is a trick. There could also be some kind of penalty for killing a teammate with your rocket back blast, and doing it too many times would kick you from the server or something.