So I noticed the classification in the Rogue Trader store today under the Fallen Captain, the Autarch, etc. etc. and it kickstarted my thinking. The Elite classes are registered as Assault and Tactical which are pretty straightforward, I'm just wondering what exactly the Command title would entail. Is there an aura thing going on? Spawn point, supply line, what's up there?

I have not seen anything on it yet. I might have missed it.....

I would imagine that they are force multipliers, possibly with auras as you describe.

From what I've seen, the Elite classes are the best at personal combat (they have the best equipment/abilites) But hero units have the 'command' role, which I believe involves large buffs to other players in the area. Command classes aren't the ultimate personal combat units, but they can provide buffs to large groups of friendly units, making them a must have in large assaults.

Sorry, no sources for you cause I'm lazy as hell, but I recall seeing similar threads in the founders lounge.

All the requisitionable spawning is and should be done from orbit - the hard decisions on battle supply should be made with a global perspective, not by a frontline soldier who's just going to keep buffing himself and his immediate surroundings. But some extra visibility tools for the autarch would be cool, like an improved tactical sight radius or persistent spotting abilities, especially if the command hierarchy could supply soldiers with an autarch upgrade when needed. That way they could be used as a tactical tool, encouraging frontline leadership behavior while not requiring them to make over-localized decision making.

I'm pretty sure the system they have planned is similar to the one you've described. The war council gets its own pool of RP to give to players in order for them to purchase elite/hero classes and vehicles. The War Council of each faction sets the factions major goals from a tactical overview map.

From the frontline, squad leaders will set goals for their squad from the map (squads consisting of up to 10 men I think) then the leaders will fight normally. If the squad is part of a strikeforce (several squads under one leader), then the strikeforce commander will mark objectives on the map (i.e defend an area), and I believe he can assign squads to different objectives. Think the platoon system in Planetside, but with a war council above the platoon leaders that can direct the entire faction.

As for command classes, they serve no actual strategic role apart from applying large buffs to soldiers around them, which is there to prevent players who don't feel up to commanding a large number of players from feeling put off from picking their factions hero class.

Command units represent Heroes like Librarians, Chaplains, Forge Lords, and Captains or Chapter Masters.
Except for the Captain and Chapter Master, each has their own special and unique set of wargear plus buffs but with some access to the command armoury.

Captains are more generic, with no special set of unique wargear, but they have a wide degree of access to the Command armoury, and can pickup weapons the above can't, plus they have buffs.

Chapter Masters are like Captains except they have even better buffs and full access to the Command armoury, so they can use weapons even the Captain can't access.

The other Factions have similar Command units.

I don't think they will let you play chapter masters, because they want to keep the game as lore-friendly as possible, and having 50+ Ultramarine chapter masters running around isn't exactly lore-friendly.

I can't remember the exact whereabouts, but one of the devs said on the class list post that each faction would have two hero units at launch (not including the ones in the Rouge Trader store). So I would assume Chapter master and Chaplin are the hero units for the Space Marines that give out buffs to allies, whereas librarians would be elite units that are very powerful combatants. This doesn't mean the Chapter master and Chaplin aren't capable fighters, they're above the basic classes. They just don't quite reach the personal combat prowess of an Elite class, in order to balance the large buffs they give. If heroes were the best fighters and provided buffs to a large number of people, they would be overpowered.

Actually I was putting TT roles into EC terms.
So we might not end up with Chapter Masters or Forge Lords, but we should be getting the others.

That sounds more likely. Though do remember they're aiming for 2 hero units for Space Marines (I can't find the source, sorry) and I'm fairly certain the Chaplain is one of them. I'm not and expert on TT, but they'll probably use the two most popular HQ units for the heroes and either add the rest later or use them as Elites. Remember, not all elite classes will be equal, some will be rarer than others, so it's entirely possible to see librarians and other TT HQ units as elite units in EC.

EDIT: I found the source for the two heroes per faction!
http://forum.eternalcrusade.com/threads/official-basic-class-list.20852/page-40#post-398399

I would hope hero units would get special abilities like artillery strikes or homing beacons to call more troops in addition to buffs but only if you follow their commands. So lets say the "hero" commands the attack of point A, everyone who attacks that point gets a buff which is doubled if he himself is present.