I'm not sure of your intentions. If it's SP then it's OK, but if it's MP I reccomend taking a look at the following easily missed fact:
Black infantry has two javelins. This is very powerful at normal gold/resource cost. You could make new light javelins with lower dmg and give them two to represent a higher rate of fire.
Just got a hilarious picture in my mind. Imagine an olympics game champion with one spear in each hand running a couple of yards and throwing them at the same time
