I like this idea - I wonder if it could also be made more interactive?
So once it is triggered, the AI takes your turns. But before each year completes, you get to review what the AI has proposed for the whole year - maybe on a whole-world map, with which units have moved where, any combat, decisions made etc. And if you disagree with what the AI has chosen to do, you can step back in and play that particular year manually, and then optionally hand back control to the AI when done.