What's the algorithm for determing what city declares independence if you're shaky or unstable? I've seen core cities declare independence fairly often, which obviously only exacerbates the situation and often leads to the civ collapsing.
It's possible for your core cities to declare independence, but only if they have multiple problems (unhealth, unhappiness, no military presence, etc.)
When there is city secession, there is a list made from the potential cities, and it's a random chance which one is chosen.
Cities can go into this list multiple times. If a city is in an unstable area, it's added to the list 8-9 times by default, if in a contested area, 4-5 times.
If a city has stability problems (like I said above), it goes into the list once if it's in a core or historic province, and 3 or more times if it's in an unstable or contested province.
So the chance is rather small for core cities if there are multiple non-core ones.
Also core cities will never revolt if you maintain them perfectly, so I find this somewhat realistic this way.
But I admit, I was thinking a lot about totally excluding core cities if you have non-core cities in your empire. Still not sure if that would be better or not.
Also, does Catholicism spread to North Africa a little too easily? I'm seeing a Catholic Morocco and Tunisia in my current game (and I do recall Tunisia being Catholic far too often in earlier versions).
Yeah, it's very hard to balance religion spread with the current mechanics.
Tried to improve it countless times, but there are still problems, especially with Orthodoxy in the NE Europe and Christianity in NW Africa.
I'm afraid I will have to rewrite the spread mechanics eventually, to be based on provinces instead.
Edit: Minor suggestion for notification of Catholics becoming Protestants in your cities when Orthodox: It seems that the Reformation among the schismatics has spread to [CITYNAME]. Much of the Catholic population there is now Protestant - not that it matters to us.
Thanks!