This is part rant, part suggestion, part stab at the general diplomacy of Vanilla.
I'm tired of starting a faction, only the be inundated with every loser on the map. I can't even find my own lords half the time during a feast/etc, because atleast 20 of these bottomfeeders wants to join my kingdom. If I have negative relations with someone, why the hell would I be ready to sign them up and give them lands? I can't remember anyone I'm on good to excellent terms with petitioning me. Its even more infuriating when they bring their men with them, claim vassalage without consent, then proceed to warm a particular section of the map until I dismiss them, as they generally are at the head of a deadly crew of Swadian children or the terrible maprats called Khergits. I never built an overdressed bronze statue asking for the poor tired and hungry.
In terms on general suggestions, I can't think of anything specific but for a game that seems intended for long term playability, well over half of the effort the Vanilla team put in went into hack and slash combat. There isn't anything that changes. Every outcome is known after the first character is over. Marriage (useful marriage), divorce, rebellions (self-initiating, claimants is a joke), peasant uprisings, religion, culture, so many overlooked aspects. (Some of that has been addressed in NE). Reminds me of a hybrid between Diablo and Total War, but without really coming out with what it wants to be or providing anything beyond the ability to pretend for a few minutes that your in a medieval setting. There's also the ever present feeling that things aren't the same for you as they are for anyone else on the map. In general the game reminds me of Lego men. Sure, they have hands, but where are the fingers. Elbowless arms, kneeless legs. Cuckolded at every step.