Uck!
Dosn't look at all like the previous weapons. It should have thicker, octangonal barrels, and a curved handle.
And for the worker, the workers job should be as simple as to gather resources for the team. Their picaxe toggles special events.
Again, "Berserker" does not sound stealthy. Maybe call him Traitor, Scout, Spy, Infiltrator, Assasin, etc.
Berserker could have a bow, pistol crossbow, tranquiliziser pistol, satchel charge, kunai, ninja star, etc as his primary weapon.
Engineers should look like an ordinary soldier, except with orange goggles and no ammo pouches. If you havn't modeled him yet.
You guys should consider releasing the first 4 basic classes, and then releasing the later ones in packs of three. Don't try to work on all the classes at the same time, or you'll end up like the Army Man mod.