Really excited for this - We should get a large scale 3CB game going once it's out!
Reference the discussion of air support above; they have confirmed on the forum thread Benzy posted above that the Germans will get access to JU-87 Stuka as close air support.
It looks like the different 'factions' so to speak would be the various divisions available, it's 9 each for Axis and Allies by the looks of it. So rather than, like War-game, building your force based on a whole nations roster (Albeit with the specific focus etc) you build a brigade from the troops available to the particular division you select