I am about 600 days in my first play through and have 3 factions almost gone and 3 have almost equal strength:
Vlandia (me): 10600 -> 10800, 13 towns
W.Empire: 10300 -> 12800, 11 towns
Khuzait: 9800 -> 10400, 14 towns
Aserai: 8300, 8 towns (initial territory)
Battania: 5900, 4 towns
Sturgia...