[Keir Maxwell]

I'm making the assumption that all humans are different, and the strong ones are given heavy armor, the agile ones are trained as light infantry,

In alot of societies how a soldier fights is determined by social factors more than individual capabilites. Some societies make a more conscious use of their resources and but most are at least as much driven by social standing. Even with Rome it is argued that after a certain date the Praetorian Guard cease to be an elite unit in reality due to the degree of corruption and nepotism involved.

Cheers

Keir