give range an accuracy penalty the farther they are from target. Bows get acc penalty per space fired and magic ranged do less damage the farther away they fire. easy fix.
As it is, late game ranged is mounds better than any melee.
will help balance them with melee too.
And of course having them ambush you is an option too.. but if you can see them on the strat map then how can they ambush you? 