Im sure this has probably been suggested before, but...
How about Guns wielded by Both Hands?
Pros: More Powerful + More shots able to be fired.
Cons: No shield, so no Blocking + Lack of Close up abilities.
Maybe able to do a Gun-Bash, with Low Damage and Knockback instead of Bringing up the shield.
It would take up One weapon slot, but you would need to re-equip the shield manually when switching.
This could give alot of variety in Guns. (E.g. Shotguns, SMGs, Rifles).
We already have Guns, why not just make their Big Brothers?
Since they don't have a shield, would they not be able to use a Lockdown class?