Yeah, Magical Military Doctrine is probably going to end up a bit like Dynasty Warriors, or Gundam. You've got a handful of individuals at the top of the power/skill curve who can absolutely mop the floor with dozens/hundreds/thousands of "regular" soldiers, but those regular soldiers are still going to be needed, because one, or even a dozen, "Ace(s)" can't be everywhere to keep their nation's territory sovereign, or secure every important facility the nation maintains. They're fantastic troubleshooters, but they can't maintain a boarder and enforce customs around the clock, especially when they do have to be off troubleshooting critical problem situations elsewhere.