With the power of modern CPU's why not Jim? Can you play in MP vs. MP?
It is not a CPU issue, it is the dynamic/random nature of the AI. When building an individual scenario we try to have the scripting guide the first 10 - 20 minutes. After that the AI-generated divergence and reactions to the players actions combine to produce highly divergent battles, even from the same starting point. For a 4 day battle, it is certain that reinforcements coming in at historical times and places would be wildly out of place. For example if a very good and aggressive Union CO pushed the CS forces back on Fredericksburg on May 1, then the reinforcing Union forces would/should have crossed quite a bit farther down river say at Scott's Ford rather than at Ely's or United States fords where they actually crossed.
MP can be player vs player or players vs the AI. There are groups that do each one. Regardless, the AI will take command of any units not under control of any player.
Design Lead: Scourge of War
"My God, if we've not got a cool brain and a big one too, to manage this affair, the nation is ruined forever." Unknown private, 14th Vermont Infantry, 2 July 1863