I can se that nicknames based on nummers are maybe not ideal like: "Two two look One five five there is a stryker left of four one" , but when you are in a squad that comunicate you can also say in squad chat: "Two look South East there is a stryker by SL four", and it's still easier to say than trying to pronounce their steam name. And that is the main goal of the system to try and get the atteintion of a spesific solder, easier. And some people don't even respond to there name in the game and probebly even less to the number idea. But you now have bothe options so if they dont respond to there number you can still se the name and call that.
So knowing which number is your's sems to be the problem with this kind of nicknaming. And since you are most likely getting a new one each game it has to be easy to remember( or be forced to stare at it the whole time).
Ok, i have tried to make a system based on colors instead of numbers more like:
And the map will look like:
I thought about giving diffrent colors (Numbers) to diffrent roles, but you don't now which roles are in a squad. And if all in a squad is a rifleman and the rifleman color is gray, everybody would be gray and the nicknames would't make a diffrence (So and icon would be better).