I have suggested this myself.  In Romance of the Three kingdoms, when a ruler dies, there is a meeting between the heirs, advisors, and generals about who should take over the leadership.  Sometimes they all agree and a new heir is named, some times, their is conflict and the nation breaks up into warring factions.  I would love that for this game.

Love the idea. I would really like to have my nation to splinter if i manage it badly or due my Sov dying.

Kinghobbit reminds me that we need some kind of little person race in this game.  Maybe all you smarty pants that made that cool elf one can make a Gnome one or something.  Little people!  On motha f'ing ponies!

Whats AoW?

Age of Wonders, which beyond small folk (it has three: halflings, dwarves, and goblins) has quite a bit Elemental can learn from. Like multiplayer that is really worth playing and archery that is not overpowered. And lets not forget that AoW has a hex grid.

The entire series is on Impulse as a bundle if you decide to get it.

Perhaps related to the charisma of the Heir in line for the throne, with the player now in their shoes. For every point of Charisma, one city (and its associated garrison) stays with him/her, and a higher chance of other family members not breaking off to join these other groups.

That would be your choice.  But I would want them to still lead my armies or guard a key city.  Besides, you would have to not beef up any of your children.  If you die and defeat your first born.  You have just delayed the fight with the one you did beef up.

Something definitely needs to be done.  I had a game going as Kraxis, and the most powerful nation on the map, Gilder, declared war on me.  A few turns later, the sovereign of Gilder, alone, marched up to my capital where nearly my entire army was garrisoned, presumably to settle the war in a duel or something, I dunno.  So I sortied out and killed him easily, causing the entire kingdom of Gilder, it's cities, it's people, it's history, to vanish without a trace.  It was like the second cataclysm or something except at least the first one left dungeons and the like behind.  Surely in this instance the worse that should happen would be for Gilder to dissolve into quarreling city states or a succession war between the successors.

(of course the AI shouldn't have kamikazed its kingdom keystone like that in the first place)