Victoria 2's cultures are in need of revision. Not only should some cultures be added (British should be divided in English, Scottish and Welsh), reworked (Dutch should be divided into Northern and Southern Dutch, the latter replacing Flemish as Southern culture is probably more similar to Flanders than to the North, with Walloon POPs becoming French) or removed (such as Texan, which is only set apart from Dixie by it's succesful revolution, which is still not a certainty in early 1836), but most importantly the rules for assimilation should be redone as well.
The mod Age of Colonialism does this real well. It limits assimilation between various culture groups, which makes sense. An Englishman can learn Portuguese, move to Brazil and after a few years be accepted by his country members as being Brazilian. Yet an English-speaking Indian can be the richest man in London and he will still be considered as Indian.
Here's a further explanation from the AoC thread:
A system like this might be refined even further by adding cultures like Mestizo and Mulatto. These people of mixed race often had a better shot at acceptance (perhaps due to racial characteristics fading away generation, after generation). This would allow Afro-Americans to first become Mulatto and then become Yankee.
The mod Age of Colonialism does this real well. It limits assimilation between various culture groups, which makes sense. An Englishman can learn Portuguese, move to Brazil and after a few years be accepted by his country members as being Brazilian. Yet an English-speaking Indian can be the richest man in London and he will still be considered as Indian.
Here's a further explanation from the AoC thread:
Only Europeans (this includes Latin Americans & Yankee/Dixie/Texan) can assimilate to other European cultures. Members of the Turko-Semitic and Persian-Turanian culture groups can assimilate to each other (Persians, Misri, Berbers, and Turks for example). Members of the south east Asian and east Asian culture groups can assimilate to each other. Members of African culture groups may assimilate to each other (this includes African diaspora). All other culture groups, native Americans (Zapotec etc), central Asians (Mongol, Tibetan etc), south Asians (Indians), may only assimilate within their own culture group.
Now you can watch as racial prejudice is accurately modeled in your game! 19th century earth was not a hyper-globalized egalitarian planet!
Are you also distraught by hordes of unaccepted pops swelling your soldiers ranks despite having a moralistic anti-foreigner society?
Now pops will consider their position in your society before wanting to fight for you. That Native-American won't want to fight for your bigoted moralism/residency USA!
A system like this might be refined even further by adding cultures like Mestizo and Mulatto. These people of mixed race often had a better shot at acceptance (perhaps due to racial characteristics fading away generation, after generation). This would allow Afro-Americans to first become Mulatto and then become Yankee.