Well, apparently, we are not to abandon nationalism as a concept... so I see no problem with up to 100 nobles all being "friends" in one realm. That's nationalism for you, right there.
that has very little to do with grand plans or global concepts, and i doubt majority of players care for theoretical background of their actions, but that is related to the fact that among 80-100 people there must be enough ambitious/nasty/drama-loving players who would do something over endless obedience, if they have chance.
this does not mean large realms would disappear, but if such unnatural element is removed, leader of such large realms would have about equal headache with outside war and interior rebellious groups.
A note on your point about "tensions": such tensions would be invoked if there was a form of ducal independence. Of course, there are always tensions in a big realm (somebody doesn't like somebody else), but once a higher authority steps in and tells both parties to play nice, it mostly puts a stop to it. With ducal independence, you'd have a nice fight over such discussion.
all about dukes. we apparently agree that thing revolve about dukes, but i have completely opposite opinion of what should happen. dukes have all bloody options in the world to do whatever they want, and the only reason for not using it is that they are so protected and untouchable in their posts that it is simply not practical for them to take risks when they can only lose.
if, for instance many times mentioned option to apply city direct taxing would go alive, i believe things would be completely different.
nobody simpy should go on forums and dev threads talking what is nationalism, and what is medieval landed lord rights - that would be resolved in-game, not on dev's desks.
rulers - put very large taxes if you want; dukes - secession, rebellion, protest, plot etc. etc. that is natural reason for ic conflict, which does not need any intervention, and i really don't know whether any talk on nationalism is needed, no devs to decide which side will win, as they did not in realm middle age, isn't it. city where i am writing this is formed through secession ca. 900 years age because that time soveriegn put too high taxes on them, they seceded and defended, why some duke should tryt todo the same in lightweight where nobody will be beheaded for real.
dukes are untouchable, they don't need more options, others need more options to press them. in super-centralized realms, dukes are heavy taxed? they need to organize, do something about that. only one duke is overtaxed as ruler dislikes him? he needs to plot, form rebellious party, anyways he needs to do something.
