Well kinslayer isn't all that bad for a long reign ruler. You essentially give up a portion of your long reign bonus, it will be no worse than it will be once you turn the kingdom over to a short reign heir. It may even give you the chance to revoke a few of the more rebellious nobles before you go through the succession.
Hmm...that's a good point. Although then I'm still left with a tough choice:
Option #1:
Kill Finn
Allow his son, Oswiu to inherit.
Pros: Still chance to inherit Norway down the road.
Cons: Very young ruler and regency. Uncle Mael-Morda becomes a Pretender to the throne and quite likely to revolt. His wife is Duchess of Moray and would likely join him. Between the two of them, they could field a formidable army.
Option #2:
Kill Finn, Oswiu and his other son Withred.
Pros: Mael-Morda will inherit, should be a stable transition of power.
Cons: Finn's wife will still become Queen of Norway in the near future, potentially ripping away a portion of Scotland with her. I could kill her too, but then I lose any near-term chance for the Norwegian crown. Alternately, I could hope that a son is born to the King of Norway, taking her out of the succession.
Really, the Norwegian question is so thorny to resolve that I'm inclined to go towards option #1. I'll probably save it and run through to see how it pans out. If the rebellions are just too much, I may try option #2. If that goes badly as well, maybe I'll try changing the inheritence laws.
Option#3: For the lulz, I could go Gavelkind and wind up giving each son one of the kingdoms, and letting them duke it out. And then as I'd be playing Finn, I could let Mael-Morda win and reunite the kingdoms.
Redking, you can't kill your kids. I think this was added is some later patch, probably the same one which made parents actually like their kids.
At first, I was going to say that's retarded because you can still execute them as prisoners, and assassinate them, why restrict plotting?
Then I realized that the AI is going to view eldest children as pretenders to the title, so it would constantly have NPCs plotting to kill their own kids. So it's a retarded solution to retarded AI.