Personally, a lot of the difficulty I have with the late game is that you have many teleporting units, rituals that can hit any province, and magic items (which teleport between labs). This means that you can't consider any one situation or area in isolation; rather you have to solve this global problem of allocating your magical resources to the parts of your empire where they will be most effective. In the early/mid game you can divide the turn up into a number of discrete local problems, since units can't really have an effect more than 3 spaces from where they currently are. So any one tactical problem shouldn't take longer than 5 minutes or so. You might recruit some units for future turns, or start moving an army from one theater of war to another, but by and large you just have to deal with a series of simple tactical problems. By the time turn 80 rolls around, you have to worry about which front could best use a thug drop, which of your several dozen thugs can make best use of each new item, whether your D6 mages would be better spent summoning thugs or casting Manifestation, and if so, which of your fronts most needs Manifestation support? I know I've spent many an hour just staring at a late-game screen, with gray matter dribbling from my ear.
Since the late game problem is so interconnected, it seems like it would be difficult to chop it up, and assign one part to one person and a second part to a second person. Or you might be able to do it, but it wouldn't be efficient, and if it's not going to be efficient why even bother?
