I think CM is the most realistic tactical game on the market, but if I were to change anything, I would provide the following options to let the player simulate the challenge of command in combat:
-The commander on the ground represent you, and therefore what is not in your line of sight you cannot observe. The action phase only shows what your commander can see from the 1st person perspective, so it is important for observers and commanders to be co-located and in the best position to command and control. High ground not only lets you see but it lets you talk on the radio. For more gameplay, a player may toggle between battalion, company, and platoon commanders if neccessary.
-The planning phase should not be done with actual terrain but with a two dimensional map..with possible and known enemy dispositions, friendly forces, and coordinating measures added. Also, maps can be wrong. This screen could also display the status of friendly forces. A commander should only be able to give orders to forces in direct line of sight, or in radio contact. Forces out of communication will follow the last order given, or simply kick-back and stop..depending on how good they are.
-Subordinate leaders should report by radio when they spot the enemy, in contact, receiving direct or indirect fire, discovered a minefield, on the move, or reach certain checkpoints and objectives (as inputed as coordinating measures by the player) so a player is forced to visualize progress. A few simple radio messages added to the game would provide the sense of what it is like to command in the field. A commander cannot micro-manage an entire battle and must choose where to be in order to most influence an operation. Of course this is how good leaders get killed. If a commander gets pinned down, his level of situational awareness should go to a near zero, until he can re-establish control over his units.
-Resuppy should have to be conducted and the future movement of the combat train must be taken into consideration (which is why roads are still so important). During a battle, units should have to conduct a resuppy as long as a vehicle or helicopter can get to them. This is especially important since missiles and other bulky ordnance items cannot be carried in sufficient quantities to last a significant engagement. Medical evacuations are also conducted simultaneously. Units out of supply and suffering many casualties should be able to reconstitute during a fight to some level. The ability to resupply forces in the field also drives tactics. Hence the phrase "amateurs talk tactics, professionals talk logistics".
-Add a "Recon" phase to allow players to insert a few reconnaisance elements in the battlefield prior to the first turn. At the planning phase of the 1st turn allow them to report what they see, as long as they are not compromised by enemy recon elements or other forces, depending on the scenario. Intelligence drives operations and is extremely vital. A civilian population friendly to one side or the other can also provide intelligence to that player. When a player inserts his recon teams..he must think about how they can observe what he wants them too, but remain survivable. A recon team out of radio contact is worthless.
I just wanted to throw these ideas out for consideration.