If I'm remembering the long dev saga for MoO3 correctly, this sounds a lot like their abandoned effort at a command point system. I liked the idea in early, broadly conceptual terms, but have never gotten to play with anything that worked that way.
There's a game for the PS3 that uses command points called Valkyria Chronicles (very good game btw, if you like squad-based strategy). It still doesn't fix the problem of turn based movement (ie, first player who moves has an advantage/disadvantage). Personally, I'd like "dead" units to get a change to counterattack "Axis & Allies" style (a board game for those who don't know).
I played a game once, one of the Romance of the Three Kingdoms ones (not much for strategy, but had some interesting ideas), that implemented multiple-turn battles -- I don't remember the exact ratio, but some number of tactical turns equalled one day (the normal unit of turns). Moreover, if your sovereign was in the battle, you couldn't interact with the rest of your empire until the battle was resolved!
I really like this idea. I've been thinking about it on and off for a while actually, but never found a good thread to bring it up (sorry, I'm not big on starting new threads). THIS would be the reason to have good AI generals to fight battles for you: You can only control 1 battle per "day" so any other battles that happen must be handled by your generals.