Hello, Black Cat.
I like your debt moves. I think they're interesting. There's a neat loop there thats really well-formulated I don't really have much constructive to say because I think I have different tastes. There's some tension between making something realistic and making a game. The choices you made were probably not the ones I would've made.
I like your idea of turning On Kings into something gameable. I haven't read the book but seems like something that could be done.
I was thinking about Graeber's anarchism more than his anthropology (I realise they blend). I'm sometimes a bit queasy about using real-world anthropology to inspire the fantastical because I still don't fully grasp where erasure and appropriation begin. I'm sure there's a way to do it but not for me right now. That said, I think you're right that there's so much wonderful anthropological work that could be injected into our understanding of the medieval part of medieval fantasy. And it's definitely more gameable than the anarchism, haha.