The last interview I read with a Gearbox person had some information on it. They said it was going to be a very similar situation to singleplayer, that is you are still in command of a squad of AI troops. So if I understand it correctly, every individual player on a server will be a captain of his squad and they will all lead their fireteams against each other.
If this is true I beleive it sounds unique and interesting, and if done correctly it could be a blast. I do see certain issues arising, namely with their supposed deviation from the standard "hitpoint" system. In another previous interview I read, they said they were going to attemp to "avoid the 1hp problem" - that is, how is a WW2 soldier fully functional with 1HP? No matter which way you look at it, in a multiplayer setting you will be coming full circle with any solution. Another problem would be, what happens when the NPC's find themselves without a team captain? Will they just stand their idling with no commands, or split off to randomly be killed as AI fodder? Who knows. I am looking forward to it though, and correct me if I'm wrong - but it is on Source still? I remember reading a (what I figured was) a botched link, stating it was on the Unreal Engine.