One of the most interesting aspects of the beginning of EUIV's time period is also one of the most unrepresented. Namely, the decline of the Feudal system in Europe. CKII is almost entirely devoted to Feudalism, while EUIV is concerns States. I suppose one could also say that Victoria 2 concerns Nationalism. But so far there is very little that represents these transitions, both of which happen in the timeframe of EUIV. At the beginning of the game, there is nothing differentiating an independent Duchy from a kingdom, for instance.
The transition away from feudalism is currently mostly represented as a switch in government from "Feudal Monarchy" to "Administrative Monarchy" at ADM tech level 12. What I suggest, in order to this change a bit more complicated, is a new government type, called a "Fief", along the same lines as an Iqta for muslims, or a Daimyo for Japan. This could be used to represent all of the sub-king level titles in Europe, under a generic title of "Duke". This is based to some extent on the systems already used to represent feudal Japan.
In order for a country to reform government type to something other than a Feudal Monarchy, you would have to have no vassals of the "Fief" government type. France, for example, would be stuck as a Feudal Monarchy until it consolidated it's rule over all it's vassals. This wouldn't really change much, time-wise. Most states would probably consolidate long before reaching ADM 12, but it would add a feeling of depth to the process (along with discouraging rampant vassalization and vassal feeding). Perhaps a Despotic Monarchy with "Fief" vassals would switch to a Feudal Monarchy, and Feudal Monarchy without could choose to become Despotic.
A fief on the other hand, would have reach a certain level of power, be independent, and be on good terms with either the Emperor (if bordering the Empire) or the Pope in order to reform it's government. Lithuania, Burgundy, and Brittany are all examples of countries this could apply to. This would give certain countries an obvious goal to strive for, and if certain restrictions were placed on Fiefs in order to limit expansion, make them more challenging. For instance, what if a Fief were not allowed to vassalize any other Fief? Or lead a personal union with a Monarchy?
The Holy Roman Empire is a bit of a unique situation. I would suggest that fiefs of the HRE be unable to change their government type. The Pope had little authority over it, and the Emperor was restricted by the Imperial Diet. This would make ever country in the HRE either a republic, a theocracy, or a fief, except for Bohemia, and Austria (after the Privilegium Maius event). This would have a number of effects. It would tend to limit players from expanding in the HRE as anyone other than Austria or Bohemia, because you wouldn't be able to get free cores from vassal feeding. It would make it harder for players to vassalize the Electors so easily. It would make the Archduchy government much more useful, and encourage players to accept it (the event should happen more certainly though). It could make forming Germany impossible for anyone that is a member (thus encouraging a historical route of forming Prussia in order to form it).
These rules should probably only apply to Catholic countries, or countries in the Holy Roman Empire. To an Orthodox ruler, most of the pretensions of Western Feudalism are meaningless, and to a Protestant, what do the opinions of the Pope matter? Once the Protestant Reformation kicks in, independent Protestant and Reformed "Fiefs" outside the Holy Roman Empire should become normal monarchies. I feel like, with a bit of experimenting, this approach could much better represent the situation at the start of the game, and the transitions during the first half of it. It also could help balance vassalization, as well as give European rulers somewhat more rational titles, without having to implement a hugely complex series of new systems or mechanics.
The transition away from feudalism is currently mostly represented as a switch in government from "Feudal Monarchy" to "Administrative Monarchy" at ADM tech level 12. What I suggest, in order to this change a bit more complicated, is a new government type, called a "Fief", along the same lines as an Iqta for muslims, or a Daimyo for Japan. This could be used to represent all of the sub-king level titles in Europe, under a generic title of "Duke". This is based to some extent on the systems already used to represent feudal Japan.
In order for a country to reform government type to something other than a Feudal Monarchy, you would have to have no vassals of the "Fief" government type. France, for example, would be stuck as a Feudal Monarchy until it consolidated it's rule over all it's vassals. This wouldn't really change much, time-wise. Most states would probably consolidate long before reaching ADM 12, but it would add a feeling of depth to the process (along with discouraging rampant vassalization and vassal feeding). Perhaps a Despotic Monarchy with "Fief" vassals would switch to a Feudal Monarchy, and Feudal Monarchy without could choose to become Despotic.
A fief on the other hand, would have reach a certain level of power, be independent, and be on good terms with either the Emperor (if bordering the Empire) or the Pope in order to reform it's government. Lithuania, Burgundy, and Brittany are all examples of countries this could apply to. This would give certain countries an obvious goal to strive for, and if certain restrictions were placed on Fiefs in order to limit expansion, make them more challenging. For instance, what if a Fief were not allowed to vassalize any other Fief? Or lead a personal union with a Monarchy?
The Holy Roman Empire is a bit of a unique situation. I would suggest that fiefs of the HRE be unable to change their government type. The Pope had little authority over it, and the Emperor was restricted by the Imperial Diet. This would make ever country in the HRE either a republic, a theocracy, or a fief, except for Bohemia, and Austria (after the Privilegium Maius event). This would have a number of effects. It would tend to limit players from expanding in the HRE as anyone other than Austria or Bohemia, because you wouldn't be able to get free cores from vassal feeding. It would make it harder for players to vassalize the Electors so easily. It would make the Archduchy government much more useful, and encourage players to accept it (the event should happen more certainly though). It could make forming Germany impossible for anyone that is a member (thus encouraging a historical route of forming Prussia in order to form it).
These rules should probably only apply to Catholic countries, or countries in the Holy Roman Empire. To an Orthodox ruler, most of the pretensions of Western Feudalism are meaningless, and to a Protestant, what do the opinions of the Pope matter? Once the Protestant Reformation kicks in, independent Protestant and Reformed "Fiefs" outside the Holy Roman Empire should become normal monarchies. I feel like, with a bit of experimenting, this approach could much better represent the situation at the start of the game, and the transitions during the first half of it. It also could help balance vassalization, as well as give European rulers somewhat more rational titles, without having to implement a hugely complex series of new systems or mechanics.