I expect a lot of nobility to die in this game. Here's how I'm thinking this. Nobles are famous and will therefore lose a lot of spirit upon death. Just sitting around in a castle would be boring so many nobles will go out and do stuff other than hiding behind walls. In a survival game with many dangers death will come often. This makes me think that the nobility will end up perma dead much more often than people are thinking they will.
This isn't even taking into consideration that some people will want to assassinate nobles. I'm just looking at it from a survival gameplay perspective.
I've already seen many of the nobles that post in the forums talk about other jobs and hobbies they'll do along with their responsiblities as king/duke/baron etc.
It's going to be a pseudo realistic world which means no healer throwing regen and shields on you and no health pot spamming. In a chaotic fight even a noob could walk over and coup de grace you.
I could be wrong about this but just to be safe you should all get with the babymaking soon as you can on release.