Hello...
I completely agree with you that just 'breaking down' units into their sub-units would, on the surface, would probably be a bad idea. But, if there where more restrictive effects for doing so then maybe it would be more reflective of such an occurrence. Such as unit cohesion. Such units that did not maintain a position or establish communication relative to the 'parent unit' or other sub-units of the same should incur some relevant and possibly significant limitations as to their abilities to perform specific functions.
Without imposing some sort of operational limits to the practice of breaking down into sub-units the game would turn into a free for all, which sometimes happens already. For instance... lets say that you have to assign a specific attribute to a deployed sub-unit or task that it is to perform. Sub-units where usually deployed with this in mind...
Such as establishing security pickets... recon patrols... spotting for artillery support... or just plain old early warning. These then should be specific to the units limits or functions as to when it is in such a status as deployed from its parent unit. Lets say you send out a recon unit to scout ahead in a forest... then that's all it should do, other then being able to fire to attack or defend itself of course. If the units involved don't have radio's in the recon unit, then it has to send back runners to relay the information as to the recon and what they observed. This should take time in accordance with the terrain movement cost and the distance from the recon unit to the parent unit. A somewhat different situation then the current 'spotting' that takes place in the game currently (!?).
Say you send out a unit to perform 'spotting'. Without portable radios they either rely on 'runners' or telephone or signal devices to relay information as to the spotting taking place. If no radio is available and phones are, then the unit can only 'spot' from the position it established for that task. Keep in mind if the unit is only spotting and not an artillery observer, it cannot directly call for indirect, or directed, fire support. This must be done by 'passing' the information on through the parent unit. Which then has to meet the requirements for passing the information on further. Once that has been done, to say a superior unit, that can call for fire support, the relative 'delay' for the organization supplying that support must be met in order to provide the fire support.
Admittedly all of this would 'complicate' things, to say the least. But, then... welcome to the real world of commanding and coordinating operations on a tactical level. We played a game the other night and it was amazing. We where able to move virtually anywhere relative to our own units and the enemy units without repercussions, other then being fired on. No effects for being out of communications with the parent unit or other units in the command. And indirect artillery support that would be the envy of modern military forces. In my opinion, having sub units and a task / ability situation would go a long way to simulating the activities of units at this level, it would also provide a challenge to using such an organization effectively.
There are of course many more examples and types of sub-units and their assigned tasks / abilities. But these are just a few examples. Does this scale support this? Not only does it 'support' it, it should be mandatory ( nah, that's a little over the top) in order to be able to perform operations at this level.
Just my opinion
Dennis