The features aren’t restricted only to abilities, but can be play style as well.
From the Wolf ET manual:
The Soldier is Enemy Territory’s Heavy Weapons Specialist. While the Soldier doesn’t have any special abilities, he is the only class that can carry heavy two-handed weapons such as the mobile MG42, Mortar, Flamethrower and Panzerfaust. Soldiers initially spawn with a load-out of 4 Hand Grenades.
The Medic can heal team-mates with Health Packs and revive dead teammates, bringing them back into combat without having to wait for the next respawn. Medics help their teammates keep on fighting. Medics can only carry the M1A1 Thompson or MP40 SMG’s and initially spawn with a load-out of one Hand Grenade.
Engineers can set and defuse Dynamite, defuse enemy Satchel Charges, plant Land Mines, build constructible objectives, and repair guns and vehicles. Almost every primary objective in Enemy Territory requires the special abilities of the Engineer. Allied Engineers can choose between the M1A1 Thompson sub machine gun or the M1 Garand rifle with M7 Grenade Launcher. Axis Engineers can choose between the MP40 sub machine gun or the K43 rifle with GPG40 GranatWerfer. Engineers spawn with an initial load-out of 4 Hand Grenades (and 5 Rifle Grenades, if they’ve chosen that rifle).
The Field Operations Specialist or Field Ops is responsible for a team’s ammunition resupply and heavy fire support. Field Ops can distribute Ammo Packs to their team-mates so that they can keep on fighting even when their initial load-out is expended. Field Ops can use call in Air Strikes for nearby targets by indicating the target with their Smoke Canister, and use their Binoculars to spot distant targets for Artillery Strikes. Field Ops can only use SMG’s and initially spawn with a load-out of 2 Hand Grenades.
The Covert Operations Specialist or Covert Ops is Enemy Territory’s espionage, reconnaissance and sabotage expert, in addition to being a deadly marksman. His skills are stealing and wearing enemy uniforms, detecting Land Mines and the stealthy sniping of unsuspecting enemies. He can also infiltrate enemy positions by using enemy Team Doors (while disguised), can report vital battlefield intelligence to his team and destroy key targets with Satchel Charges.
The classes in dirty bomb are no different from the classes in Brink and Enemy Territory Quake Wars, all made by Splash Damage.
The class in DB must have some abilities that match that of the ET counterpart, but must not have any features from any other class.
Soldier/Assault. All Assault mercs can carry heavy weapons. Mercs of other classes don’t have the grenade launcher or Minigun ability, and they do not have a loadout card featuring the K121 or MK Thunder’s weapon. Fragger’s grenades serve sort of like the fact that Soldiers in ET carry 4 grenades.
Medic. Heal and Revive. No other merc class can do this. In Dirty Bomb any merc can revive, but only medics can instant revive.
Engineer. They are objective specialists, coupled with the fact that in ET, only engineers can do objectives. No other class is good at doing objectives. The fact that Engineers have 4 grenades is similar to how Fletcher can use his sticky bombs like a grenade. Non Engineer mercs don’t fit this description.
Field Ops/Fire Support. They give ammo and they have a fire support ability. Arty’s ability only has one barrage, while the one in ET has 4 barrages. The 4 barrage artillery denies an area, similar to Stokers molotov. No other mercs who aren’t fire support mercs fit the Field Ops description.
Covert Ops/Recon. All recon mercs in dirty bomb have at least one job between espionage, reconnaissance, sabotage, marksman, or infiltration. No other mercs who aren’t recon mercs fit the Covert Ops description, and no Recon merc fits the description of the other classes.
Now why this thread? Here is an argument. Phantom is a Recon or an Assault? From what I said above, he isn’t an assault. Why? He doesn’t have a K121 or a MK Thunder’s weapon for a loadout card. He can’t do anything as a medic, engineer, or fire support. He does have the ability to infiltrate, which makes him a Recon merc.
This is true for the first 20 mercs, including Turtle, Thunder, and Aimee. The classes association with a merc is meant to be loosely based anyway, so it isn’t to say that we might get a new merc that can do both medic and recon stuff. Right now, with the first 20 mercs, they are all associated with only one class, and they do not match the description for any other class.

