Well, you could use csg to literally blow holes in armour, and the user can see how damaged his armour is, there is no "armour left" variable.
(theres an example of replacing a basic guage with something more realistic)
This way, if you shoot the same area twice, you get twice the effect, with an armour guage, this is not possible.
Then you fire rays through the holes to the body, and see if you intersect any internal organs or not, and if you hit an organ, then maybe you could have a metre for time left to live as blood spills out internally and starts funnelling out of your mouth.
Well you could use numbers sometimes, when its ok to do so, but a more advanced game would use simple metres and guages less, im pretty sure.
Imagine a tank game, and you literally ricoche the missile off the angle of the armour it hit, for more or less penetration, theres countless things that games have never implemented that would improve realism.
What im saying sounds dumb to you because it has been neglected so much in programming for simplicity instead that my argument sounds weak.
There, I explained.