Your favorite hero...

Faydhean always had archers, even when I played as him, and on a simple map! I buy them first!

In version 1.5, you need level 6 for the city to build archers. I don't remember for the Druids. Unless they are in the starting team...

The strength of the initial volley heavily depends on the hero's level. It can be frustrating when the hero's archers, at level 30 in mission 5 of the campaign, destroy a stack of unupgraded skeletons, while the archers remain.