There was that movie where the mobster told the incompetent hitman - "Just walk up to them, put the gun to their head and pull the trigger. That way, you can be sure."

Then he put a gun to his head and pulled the trigger (because his uzi attack had failed to kill the target)

Anyway, hard to beat the classics. Until the drone can lie in wait, identify the target itself, home in on it and explode at point blank range, well then we haven't gotten close to the traditional approach.