Exactly. The typical example of weak central authority and strong local rule is the Holy Roman Empire (famously described by Voltaire as "This agglomeration which was called and which still calls itself the Holy Roman Empire was neither holy, nor Roman, nor an empire."), yet this is presented as a single monolithic monster of a nation in this time lapse.

And as a person who has sunken more time than he cares to admit into Crusader Kings II (and Europa Universalis IV), I can only add more praise to the level of detail crammed into Crusader Kings II. It really is unlike any other strategy game in its historic accuracy, at least when you consider the late dark ages, and the drama involved with being a ruler of a feudal dynasty is great fun.