You guys might be forgetting one crucial fact: An improved accuracy score may simply decrease the effectiveness of armour (if you'll allow me to geek out for an example: Legolas telling the elf archers at Helm's Deep where the armour on the Uruk-hai is weakest.) The real question I have to wonder: Are bow hero units worth it? Also, I don't think you should measure the kills per volley, but perhaps the kills in a given 30 seconds period or something, to allow for reload speed to come into account.