With MTW I found a lot depended on what level you played the game on, Easy, mid or hard.

Tactics seemed to work ok on med and easy but they needed changing on hard.

Many a game as HRE on hard I found provinces would rebel, so it made it much harder to achieve global domination.

I would like to see more provinces, and make it harder to capture them. Taking the hundred years war as an example, England historically controlled large areas of France, but not all the towns and cities.

So for me the more provinces the better this would allow for smaller factions thus it would take more time. for example, using the hundrd years war again, sorry but its a very good example, Brittany and Flanders would be smaller independant kingdoms, or serfdoms, if you like. Only controlling a few provinces, where as France would be a massive country of loads of provinces.

For what I can see from the Campaign map of MTW2, Northern France is five provinces which have a city in Brittany either Rennes or Nantes I guess, Caen in Normandy, Bruges in Flanders, Paris in Ile-de-France and Reims in I guess champagne. So this means we have no Rouen, Calais or probably no Orleans. This looks like one provinces even 100 miles or so.

The only way to stop the world empire would be, using France again, change this from 3 northern coast provinces to say 6. Two in Brittany, Two in Normandy, one in Picardy/ Artois and one in Flanders. Three hundred miles should take a long time to march. It we copied this across the entire map, we find that it becomes harder, more provinces, loads of small little states. It would take a lot more time to conquer and you might find that it was almost impossible to take more than about 1/4 to 1/2.