I would have to cast my vote for the eastern steppe provinces for all the reasons St. Jimmy stated. They have incredibly slow growth, the spawning ground of Timerids and Mongols, and most importantly, are huge. This makes them bad troop and money producing factories. The only good thing about them is your ability to see an enemy coming because the provinces are so large, yet this is counter balanced by how far you have to travel to keep it rebel free.

I tried a campaign in SS as the Cumans, and only lasted 10 or so turns because of how large and lowly populated the provinces were. I didn’t even have all the watchtowers up when I quite. Perhaps I should have packed up everything and migrated across the map.

Anonymous II, I play my campaigns exactly like you. Keep a good rep, tech up and take one enemy out at a time. I feel as though this is a more realistic approach to the game. Also, I found in SS where the diplomacy works better, playing in such a manner is an advantage because of the AI's ability to spam decent stacks, making it difficult to fight more than two factions.