And two - in the campaign, upgraded horses and fireflies are more effective than archers.
Having fireflies is essential to go first. With the first turn, reinforce (level 2) the horses, and then you can send them into the fray without worrying too much about losses.
Spending upgrades on arbalesters (+3% damage per shot) - the only ranged unit in the entire faction - is the height of irresponsibility :) What do you do if the arbalesters are taken out? Passive perks for defense and retaliatory strikes, and battle cries - that's what this faction needs.
And, of course, use the guardian angel wisely.