That proportion is pretty decent if you count attacking civilians into play.
That logic behind the proportion is fine but the problem is Civilians aren't marked, that's why a wanted or value system should be implemented for each civilians performance and slots should be favored based on that.
Most of the time its' 14 vs 5, I even had a 10 vs 1 (me ofc), Add NRG+Assisting Civilians into the picture and RIP Balance, nobody would even be motivated to kill president since risk-reward is unattractive,with latter being constant no matter what the odds, along with the terrible chase system for terros.