i'd actually like to have some of kind of mechanics to represent minorities, but this game is already a bit too old to have such a change in its mechanics.As a sort of compromise, minorities should be represented by modifiers. They should have a religion by default that is native to their culture group (ex: Danish Catholic, Greek Orthodox, Sunni Turkish). There could be three levels: small, medium, large. Each gives extra development. If the minority grows beyond the province's basic main culture, it will flip. You can of course convert the minorities in terms of religion and culture which should take a while based on how big they are but would be rewarding in the long-term. This would also helpful for CBs in the later game where province cost will be lower if you have a large minority of an accepted culture in an enemy province.
Accepting cultures should also give a temporary penalty to stability costs as it would represent in an abstract way those who are native to the land being disgruntled that others are getting the same privileges as them.
Anyway, if we had to consider a significant minority in most of Castille (including Castillian Andalusia), it would be the Sephardi Jews, without any doubt. They were far more numerous and influential than the moriscos.
- 1