What I didn't anticipate is that my heir, currently known as king Ordulf I of Germany, would get the
kinslayer attribute for this joke. In hindsight I might've done something against the plot, because poor Magnus died at 70. Chances are pretty slim he would've gotten much older, so this whole exercise is a bit pointless. But hey, it fits the story of the Billung dynasty!
Right after this event I created Germany and saved. I'll have to do some puzzling to figure out who I can give a duchy without repercussions (for instance: I have a CB against the court dwarf for his last county in Gelre (because of my duchy of Gelre), if I give the duchy to a vassal, will I keep the CB? I assume I get a "press a claim" CB), and without getting too strong. Luckily the duchy of Braunschweig is large and strong, so I feel reasonably safe from revolts. And with this kinslayer attribute I can expect revolts... Besides duchies I need to get rid of half of my counties. Hopefully my king title will make it easier to invite people to my court, since I'm not sure there are enough people in my realm to receive all that property...
One more thing: I figured out what I like about this game. Like Colonization it revolves around the management of people. EU3 is more like civ, where you're maximizing gold. Coming from EU3 I needed time to get into this mindset. Obviously col revolves around the production and trade of goods as well, and that part is lacking. Perhaps it's in the new Republic DLC.