heres a suggestion:
unique weapons(1 for each class)
so you will have best sword,bow,xbow,etc but make it so it will only be alowed 1 per team and it should be the weapon of the leader
that way there wont be any overpowered team.
for example:
the brigads > best dager
town watch > spear?
archers > best bow
knights > best sword
i just made this up...what do you think