If there were a Return To Castle Wolfenstein Expansion Pack, and I'm not saying there is, it might include another class altogether - one that specializes in Covert Operations and sneaky stuff. It might include a multiplayer map that takes place in the Single Player campaign's Forest level. Engineers might enjoy an expanded role, with the ability to possibly build bridges, sniper nests, and machinegun emplacements. They might also leverage powerful new weapons, like Land Mines or Grenade Launchers. Soldiers could appreciate the FG42 Paratrooper rifle, or even a mobile MG42. This game, which exists purely in the realm of Theory, might include full bot support, were it to be an actual product that was in alpha now.
(CW)TB