Maybe for sieges, for attackers and defenders alike.
Would require a new item--a brazier or the like. To use fire arrows, you'd have to stand within arm's reach of it, and if you move away the arrow doesn't light.
It'd also require "Oh god I'm on fire" animations and shit. Plus calculations for damage over time and burning, to apply for both people and buildings. What would the purpose of burning down buildings be in Strat anyway? Decreased population on the map? Decreased prosperity?
No, I don't see this being worth it, especially if it's just for combat's sake.