Hi
One thing you could try is when you own a large amount of the world is let the AI control your taxes, unit and building production. This seams to solve the problem of provinces rebeling. One other is to let the AI auto assign titles because it chooses high accum generals which benfit the province they work in. Just as a side note I don't advise this early in the campaign as the AI is pretty out of it, but when all your concerned of is moving key armies to crush remaining factions it really frees up your time.