Hm... Well, my end-vision of my mod plans on increasing civil war frequency... But I don't really see it as an increase in frequency, so much as a potential consequence of mishandling internal politics.
Version .11, for instance, will have a few more possible consequences - as an example, if your ruler is too friendly towards a neighboring nation while militant, charismatic anti-(neighbor's culture) grow popular, an event chain will threaten a civil war, as he incites a civil war to save the nation. The peaceful, charismatic anti-(neighbor's culture), on the other hand, are triggered by wealth instead of popularity, and instead will seek to assassinate you or manufacture issues to harm your relations

.
Also, my new events for dealing with disloyal subjects can spark a civil war if misused; if you're executing a subject who is too charismatic or popular, there's a minor chance that he begin a civil war, and a moderate chance that he can start a rebellion. Executing a group of conspirators carries a much higher chance of starting a civil war, depending on what point you intervene; starting too early, though, risks executing a group of perfectly safe characters (who, depending on how cruel I'm feeling, might have been working on something nice for you instead

... But I haven't coded that sequence yet, and may end up discarding it ^_^0 .). I thought it necessary to include more options to dispose of disloyal characters, since I've been decreasing the general loyalty levels, but I didn't think it ought be
easy 
... And, as usual, charisma and finesse are vital characteristics here; a low finesse score will leave your charges looking flimsy and ill-applied, while a low charisma score will leave you ill-able to sooth the concerns of other characters. What does that mean in game terms? Well, you'll find out

...