Realistic Ancient Soldiering was basically getting a bunch of people to one place in the best condition possible to fight. That is why if you look at the soldier skills, logistics had the greatest emphasis.
Getting to Place X is always troublesome and have many factors that can affect the out come of the battle: Desertion, Lack of supplies, Weather, Low-Morale, Confusion, etc. That is why having combat skills at 10-11 is quite common and survivable.
If a bunch of disorganized barbarians meet a bunch of organized soldiers, chances are the soldiers will be in a better condition to fight. Having brought all that "Capital" or Equipment with them these soldiers are already at a big advantage compared to the barbarian. Discipline also goes a long way in this encounter, since it cuts down the amount of stupidity.
So a soldiers just has to do what he is told. At Block-10 (+2 from DB), Attack-10/Parry-10 and armor a soldier will outlast a Block-9, Attack-11, Parry-9, and being at a better FP condition than the disorganized side allows for acceptable losses to the organized side.
An adventure can be about getting there at the most opportune moment.
Having more appreciation of obstacles, challenges, and the technology that has allowed us to travel great distances in much greater comfort and safety, has made me realize how much harder it is to organize that it is to fight.
Fighting is easy, its a few things that hold your attention. Traveling and Organization is hard, because there is a lot of planning, improv, and limitations that compound over time and distance.