Thanks for the answers! For some reason, I didn't even think about either of these options (but then again, no one can think of everything): the soldier being a cut above the others or the soldier trains a little harder to become a Fighter instead of staying a Warrior. In real life, there are people who are just naturally skilled (Thus automatically being a Fighter) and those who aren't, but they work hard at what they do (Thus going from Warrior to Fighter). So occasionally, in a patrol, there should be a Fighter mixed in within a patrol of Warriors.
I don't know if I particularly like the idea of 'more levels, higher rank' but then again, I don't know if there is a way it should be done instead. Occasionally, there are inexperienced officers, so they might be a lower level than their subordinates, but generally, after a certain amount of experience/training, you are advanced in rank (Though this is perhaps not completely accurate during times of war, though they should make up for it by the heavy experiences they are learning about during such a difficult period). In Dnd, it seems that the only way to show a reward of gaining enough experience to advance in anything is by leveling, in rank or class. Thus, the easiest way to show a higher rank is to have a higher level.
