Of course, just burning the houses wouldn't be much good. It would merely create a bit of chaos on the battlefield – the houses weren't so tightly packed that they'd form a wall to trap the inhabitants in.
It would have merely turned their battle into a long one, a battle of endurance. The Yarmdon would have been forced to tackle the soldiers in much the same way as they had been forced to tackle the fort – up close and personal. The only difference would have been in the efficacy of their arrows.
It was a trade-off, there. Arrow cover, versus more effective utilisation of the infantry, with the help of the fort's stakes and trenches. With the Stormfront soldiers in question, trained in group combat as they were, and proficient with the lengthy spear, it was obvious that the fort would be more effective.
