A thing I always wanted in Victoria - when I had conquered vast expanses of the world, and having brought the light of my wisdom to all sorts of unfortunate and primitive souls on the face of this good earth...I always wanted a degree of self-determination other than actually modding the game 
What I mean is - I want an in-game mechanism that will allow me to rename my nation (dominant culture, national identity, whatever) - AFTER a certain degree of expansion and multi-ethnicity within my borders...
For instance I enjoyed on occasion conquering Europe as Switzerland... A bit unrealistic obviously, but it brought me great joy and amusement, and there's something glorious in having a huge European super-state with a capital in the Alps... What can I say, I'm the worst kind of megalomaniac...
Well, obviously, I couldn't remain as Switzerland, so I renamed my nation with a multitude of names over the years (oh yes, many many years of Vicky), such as the United Federation of Nations, European Dominion blabla (errr the European Union too, lol)... The dominant culture had to be changed as well, so alongside the French, German and Italian majorities there was a growing nation named either European, or just something plain like "Federal Citizen", whatever...
My point is this, finally (and please excuse the absurd example but I'm sure most of you have had the same issue) - after a point where I have obviously achieved feats that do not conform with history (another example, let's say, starting as China and conquering all of Asia and India ugh) - the game might offer me an event that presents me with an option of forming a brand new national identity.
This would be entirely optional of course, and if the developers should like the idea but lack the practical element of actually making it work - they might implement their own hard coded mechanisms. An example to this effect: the world map is divided into several "unseen" regions. The player, after conquest (or any other means of appropriating territory) of 100% of this region, is presented with an option of forming a new national identity (including a name for the entire state as well as a new, federal or however unified, ethnicity). This option might be in form of a choice depending on the form of government. For instance, if I as China ruled as a Const. Monarchy conquer entire Asia, I might be presented with an option of renaming my nation as "Commonwealth of Asia", or something along those lines. This, of course, after I've conquered the entire region that would qualify me for such an event, and AFTER my starting dominant culture(s) is the majority (even a certain high degree of majority if you will). Just a suggestion.
This would obviously require a greater investment of imagination, but why not. Isn't deviation from history kind of the whole point?
And I think it would increase immersion.
Regarding the inevitable comments of the following type: "lol".
Well, I'd just like to point out that history is full of examples where a multi-ethnic nation might choose to redefine its national identity to solidify their sovereignty and unionism, even with generic self-explanatory names. The United Kingdom for example. How generic is that? With a name like that you could easily rule the Scots, the Welsh and the Irish without anyone complaining about the name favouring a single nation, regardless of actual history
The "British" nation is an excellent example, and in terms of my proposal, the qualifying region is obviously Britain
Let's move on, the united States of America
You could rule the entire western hemisphere with a name like that.
To further amplify my point - in real life, you could never rule Italy and France (for example) as Germany, and have a national German national identity/dominant culture. No way in a cold Hell
In a thousand years you couldn't make an Italian consider himself as part of a German nation 
Ok, there's my proposal, thank you for reading, if you had the nerve
Cheers, good luck Vicky 2, can't wait!
What I mean is - I want an in-game mechanism that will allow me to rename my nation (dominant culture, national identity, whatever) - AFTER a certain degree of expansion and multi-ethnicity within my borders...
For instance I enjoyed on occasion conquering Europe as Switzerland... A bit unrealistic obviously, but it brought me great joy and amusement, and there's something glorious in having a huge European super-state with a capital in the Alps... What can I say, I'm the worst kind of megalomaniac...
Well, obviously, I couldn't remain as Switzerland, so I renamed my nation with a multitude of names over the years (oh yes, many many years of Vicky), such as the United Federation of Nations, European Dominion blabla (errr the European Union too, lol)... The dominant culture had to be changed as well, so alongside the French, German and Italian majorities there was a growing nation named either European, or just something plain like "Federal Citizen", whatever...
My point is this, finally (and please excuse the absurd example but I'm sure most of you have had the same issue) - after a point where I have obviously achieved feats that do not conform with history (another example, let's say, starting as China and conquering all of Asia and India ugh) - the game might offer me an event that presents me with an option of forming a brand new national identity.
This would be entirely optional of course, and if the developers should like the idea but lack the practical element of actually making it work - they might implement their own hard coded mechanisms. An example to this effect: the world map is divided into several "unseen" regions. The player, after conquest (or any other means of appropriating territory) of 100% of this region, is presented with an option of forming a new national identity (including a name for the entire state as well as a new, federal or however unified, ethnicity). This option might be in form of a choice depending on the form of government. For instance, if I as China ruled as a Const. Monarchy conquer entire Asia, I might be presented with an option of renaming my nation as "Commonwealth of Asia", or something along those lines. This, of course, after I've conquered the entire region that would qualify me for such an event, and AFTER my starting dominant culture(s) is the majority (even a certain high degree of majority if you will). Just a suggestion.
This would obviously require a greater investment of imagination, but why not. Isn't deviation from history kind of the whole point?
Regarding the inevitable comments of the following type: "lol".
Ok, there's my proposal, thank you for reading, if you had the nerve