There are three mechanics I want in the future: chain of command, fog of war, and logistics. The chain of command and fog of war would counterbalance the aegis of the player. As in real war, the CoC mechanic can be disrupted, even broken, once melee's joined. Warscape would process all the unit stat logs, such as unit strength, proximity to generals, whether the captain is alive, who's on their flanks, discipline and training, a unit's chevrons, etc. then judge whether that unit can respond to the player's commands. Logistics has always belonged center stage with settlement planning, technology trees, and tactical battles. The first step is introducing provisions, and this would determine action points. Once this is done, logistics should be made a General's attribute. Then the new attribute could be assigned it's three character abilities: foraging, raiding, and supply train.
Foraging is simply the exploitation of a foreign power's produce, which has been the behavior of armies since the very beginning. Raiding needs no introduction, but I would like to see raids become an integral part of the campaign, as they have always been the way of armies. Two effects I have in mind are mitigating upkeep and cutting military administration, as well as stocking some provisions. Finally, supply trains. Think trade lanes, and you've got it. Supply trains would link the general's army to the last settlement they garrisoned. The settlement would accrue war weariness, on top of a hit to produce, while the army has provisions for any extended campaign.
The number of trains any settlement can supply would be reasonably low, so the AI couldn't exploit itself to death. If the settlement was ever lost, or the distance became too great, the stranded army would suffer irremediable loss to desertion, attrition, disease and mutiny. Another scenario may be an enemy raid on the train itself. Unlike piracy, the aggressor here would need to win a tactical battle. In the event the battle was lost, the supply train is gone, not to mention the casualties taken. Whatever the reason if a supply train is lost, armies of any real substance would need to disband, fall back to a friendly, very productive region, or blitz a nearby settlement and hope to garrison there, because raiding and foraging alone wouldn't support them.
I've got a siege war system on paper somewhere. Wrote it back when I was an active modder for S2/R2, when my main concern was battle AI, but there's no point even thinking about that shit. I'd rather keep it to meself and possibly go the Ultimate General route.
You mean how is shifting focus from historical to high fantasy relevant?