There was a lot of discussion recently concerning the problem known as "Micromanagement hell". Basically, the number of tasks required for competitive play in late game is overwhelming and tiresome for a single player. There were several good suggestions made, and I wish to add another one.
Basically, the question is: is it possible to have one nation in MP run by two or more players managing different areas? Technically, I see no problem here: players just send the turn to the next one in agreed order, and the last one submits the turn.
For example: a player's nation is eliminated somewhere in mid-game as it usually happens, but instead of just dropping out, he is offered a commanding position in another player's rapidly growing empire. He can be a magistrate in charge of micromanaging several provinces, or something like that.
I do not know if this idea can be actually used in a game, but I just thought of it as of an interesting possibility that I did not see mentioned here before. Maybe it will be useful for somebody