And here's some info regarding some weird CTDs that occurred during the loading screen for no apparent reason:
About 7 units (Voi,DanishNobles,MazovianSpearmen, RussianHalberdiers,PestMilitia,NeapolitanInfantry,CatalonianFootKnights) who use 2 specific "body types" can cause a CTD when they are picked and their faction colour is among the new faction ones, apart from their own (eg. Novgorod Militia can use the novgorod faction colours without problems). So until this issue is taken care of, it's advisable that you avoid taking a different new faction colour when playing with the Polish,the Novgorodians, the Russians/Kievans, the Hungarians, the Sicilians, the Aragonese and the Papacy, at least if you intend on using the above-mentioned units.