To add to (or to brainstorm about) EViLMinD's GREAT(!) idea:
It sounds like a "chain of command" thing with that Commander/Captain thing. If Relic manages to implement such a thing, they's the bomb for sure.
For that, I would suggest "truer mimicking" (in a loose gameplay-fitting sense) of chain of command with even more players. One Commander (a Major or whatever) who controls building/teching/etc. He tells the Captain where to move and what things to do first. Raw strategy, and he only has a special map view, and no sight of the actual 3D battlefield.
The Captain controls the overall troops like we're used to right now, he just can't do the building/teching/etc., and he has to follow Commander's orders.
But what if there are more players in a game? Then the Captain has a nice role too if we include them. The Captain will then very rawly direct overall troops (grouped forces of squads, for instance) to execute the raw strategical orders of the Commander he receives as "important points". A Lieutenant (or just whatever you're to call him) will have control over grouped squads/units as we know them now, and has no control over the other higher aspects. The Captain will have to deal with reinforcements btw, and logistics.
But what if there's even more players? A Sergeant could come into play. He has the actual third-person (or first-person) view and with this I'm thinking of a Brothers in Arms kinda control scheme. He must tell his AI squad how to maneuver and beat the enemy, while he himself carries a weapon too.
And now.... if there's a lot of players, if that's at all possible in one game, the individual soldiers who take orders from the Sergeant. Couple of soldiers per squad, plus Corporal who's rated as a better soldier who takes over squad command when Sergeant dies.
Or maybe when players come in they should get a certain role higher than the players already there based on ranking?
I'm imagining that when an officer commands his lower officer, a clear waypoint or mark is shown somehow. For instance: when the Commander tells the Captain to take care of something first, he should just click on his specialized map, and then the Captain will see it on his own map, and so on. And the third-person players will see it on their own map that's moving along with their movement (rotating).
It's nice that as soon as a new player comes in he will have control over something lower in command if he connects later to a game. If you miss players to fill roles, AI follows orders like usual, but as soon as a player comes in he takes that part over. For instance: a Sergeant comes in and he then controls (if this unit is made of course) his AI squad(s), but if then a Soldier comes in he will be a part of this squad WITH AI Soldiers, and they might get filled up by human players or not.
Of course with the map clicking there could be certain "mutiny". Example: Commander clicks his map to tell his Captain to do this, but the Captain might think otherwise, and doesn't give the information to his lower officer, or he has other plans, and so forth. This could easily break down the flow of command and effectiveness, so each player really contributes something.
Shit, I like this.