A good game never tries to force players into doing something just for the sake of realism if the players demonstrate that they will not want to do it. Forcing it will only make people begrudgingly go along, but who knows, maybe some people might see it as the only reality in this game, thus have no problems with it.
Right now there are a lot of players who understand that such is by far not the only system, and most of them probably believe that it is not the system they would like to be restricted to. Now the interesting point you make about how the Middle Ages were an interesting time period is itself also steeped in fantasy. I'm sure no one has yet RP'd his knight as being properly accurate for the time period by relieving himself of his bodily wastes during a long battle. You aren't getting out of armor in the middle of battle because it's too hard to do it yourself and you'd be a dead moron when an enemy arrow pierces your chest. So if you drank a bit too much mead or had a bad pork chop the night before guess where you do your business?
Oh, and let's see...Mathematics finally started developing once people stopped using I's and V's and X's to count but I'm pretty sure the reality wasn't as cool as having an epic journey from across the Middle East back to Europe to bring back the great gift of Arabic numerals.
What about decorum? I see a ton of messages that seriously break any sort of acceptable speech that a noble of the time period would have been allowed to say without being laughed out of court or worse.
But hey, we can't give people lessons in proper etiquette, nor are we all PhDs in Medieval Studies, nor do people like it when we decide to be a bit too accurate and graphic with the events of the time period. All acceptable. What makes this stuff about realm organization unacceptable? I see nothing wrong, since it is easily accessible to people now. They can actually understand realm level government. Relatively fewer people of the modern age understand the system of duchies. It would simply be a new mechanic for them to learn, if anything., and achieve possibly no real RP value.
