I don't think that the world map should be balanced, I think an unbalanced map is more interesting. Of course, it shouldn't be too imbalanced like in the earlier EA version where the Khuzait or SE took over the whole map in 5-10 years. The map is nowhere near as imbalanced as people are implying it to be, Battania doesn't get destroyed every single time, nor does it die off after 3-5 in game years if it does indeed do badly. Kingdoms in this game are very resilient (way too resilient in the case of fiefless kingdoms, but that's a separate subject) and don't get steamrolled that easily.
I actually would like more asymmetric gameplay added to the game, such as the option to pledge allegiance to a kingdom with a single town, perhaps on the mirrored Cyprus island in the fake-Mediterranean (as a Venice based faction maybe?), or perhaps as a weak coalition of small kingdoms in the fake-Caucasus region between Tyal, Amprela, Makeb & Baltakhand (based on medieval Georgian, Armenian, Circassian, etc. kingdoms). What can actually be added to the base game sandbox quite easily, would be to have an option to have a unified, pre-civil war Empire led by Arenicos or Neretzes as a scenario at character creation. The Empire maybe could be at war with several factions at the start and we could try to destroy it or defend it, like the "fall or Rome" scenario in Civ 5.