True, though every soldier goes through basic training so there physical fitness should be about the same. Of course every individual is different so there could be a random factor with it, say 5-8%.
The Module could also include different settings for different groups, say you have basic infantry, recon teams, and sniper teams. They can all be set differently, this could also give the recon role a significant advantage over regular infantry depending on what the mission dev chooses.
Bots. They should by default have the same settings as players (I believe that is the case right now). Making a separate module for bots would work, this module will by default mimic the settings of the players but can be freely adjusted.
As your request is about the configuration of each individual unit, in my opinion that would be bad. With that option it would be possible to create super soldiers, and we all know that Captain America does not really exist. Plus, I would not want to configure all 60 playable slots individually.