I had an idea that a good way to balance these heavy archer/shock-infantry classes and provide a unique playstyle would be to severely limit their ammo for their bows. They can certainly hold their own in melee combat, and there is a good scavenging system already in place, so it could be interesting if they were required to scavenge arrows from the ground/shields to keep their ranged damage potential.
It would promote a different style of play than other archer classes and would make each shot more valuable to promote some interesting decision making. 30 - 40 arrows (only checking from the armory, couldn't find a match to test so forgive me if this is wrong) seems like a bit too much for these classes and allows them to just spam arrows until one lands.
Furthermore, it would force these classes to have to change positions quite regularly to restock on ammo. As it is now, they mostly act as archers until they have been pushed where they draw out their secondary (usually super powerful) weapon.
This may not fix all of the problems they pose, and the netcode would have to be super secure so as not to make items disappear, but I think it could be an avenue for balancing these classes worth investigating.