He just hasn't been interesting in the farming arc. Seeing the disembodied head of your murdered father is all well and good, but his actions and motives are boring. I'd compare him to Shakespeare's Richard III: He is an interesting character when trying to take the throne, but he loses all of that when he finally gets it.
The quest for power is a lot more interesting than the exercising of it, especially since the former generally requires a lot of wit while the latter can and does involve overt displays of power and authority.
I see your point, Reclaimer. Though, I cannot say I agree with it. I'm very interested how will Yukimura depict future political life of Knut. I mean, there are "quest for power" stories but many of them end when a character reaches his goal and… That's it. I find that boring and lame. I want to see Knut's life at the throne. I don't care if Yukimura spends XX chapters telling us about Knut's position and how he tries to solve various problems in his kingdom.
Speaking of Knut and kingdoms, so far in Vinland Saga, there was only one point in the story where I was somewhat disappointed. I'm talking about Knut's conquer of England. With return of Ethelred II. England once again sank into waters of war. There were battles when Ethelred and his followers had upper hand and Knut had to fall back. I actually expected great war campaign spanning 10-20 chapters. And Yukimura summed it up in no more than two chapters. I understand his reasons but as I said it was a little bit disappointing. Well, Vinland Saga is still the best manga I've read so far… and I kind of expect that it'll stay at that for a long time and probably even forever.