In the games I've played I've noted very few absolutes, largely because I like to play as different factions and I alternate the storyline based on the fact that I tend to dominate my region. What I have noted:

1) eggys ALWAYS end up as the #2 power and sometimes hold the #1 spot a while, even when I played the Elmos I went after spain and argon first then fought of the parade of crusades from france.
2) the feared golden horde always retreat when challenged and rarely threaten anyone after they take the steppes.
3) The Danes, the Pope, Aragonesse and the rebels all stay relatively passive and rarely threaten even exposed flanks. They take no terittories.
4) Turks are always in the top 3-4 factions to get greased.
5) Byz always end up on Crete and/or Cyprus.
6) Huns always turn on the Poles and always kick their butt.
7) If England doesn't attack France, the HRE dies.
8) the russians always seem to lose and retake Livona from the rebels.

Aside from these re-occuring themes I'm suprised and pleased by the dynamic outcomes of the games I've played.