the only real change I'd like to see is to have Nomads completely unable to revoke titles from Feudal/Iqta/Tribal vassals
Maybe this helps with AI nomads, that I don't know.
Personally as a player I found that the most powerful option was almost always this:
1 - Get population up to around 80% of the limit
2 - Give away a few counties to a clan that I'm going to absorb later, to get 90% of limit of pop
3 - Give every other clan 1 county, maintain the clan limit always
4 - Set up a string of invasions simultaneously against anyone in diplomatic range that I wanted to take in one swipe (e.g., "Eastern Europe")
5 - Siege every province down at the county (top) level
6 - Peace out, hold everything personally (baron vassals or not, didn't see the point really, had too much gold from pillaging and pop tax to fool around with it)
At least that is how I did a "Khan of Khans" game with the Mongols at 1220. Took 63 years (but certainly could be done much faster than that).