Another way to cut down on rebels in your land is to have the whole area garrisoned. If a lot of your land is not visible it means you are not keeping a watchfull eye on the land wich provokes rebellions.

What I do is I garrison the city for a loyal population. Then I garrison around the province so that nothing goes unseen in my territory. Also this method seems to make the city grow faster and actually reduces the garrison needed as I guess the people feel safer knowing the bandits are'nt running around robbing the masses. Also traders will want to come to your city because they know there are less chances of them being ambushed.

Also garrisoning the whole province allows you to see advancing armies before they get to your city so it's a doubl bonus.

Ever since I've been garrisong the whole territory instead of just the city, I noticed a lot less rebels popping up and you ca'nt ignore the rebels as it seems to make problems get worse. So if you ignore them they will just keep getting bigger and bigger