do you think though that it is worse for a random member of the dominant culture to know about pre-Tokugawa Japan only from Shogun or not to know anything about it at all?

I think this is a false dichotomy that leaves POC writers completely out of the picture.

I'm not saying that a work of cultural appropriation is by necessity bad, or that it can't lead to readers wanting to learn more about the culture in question. But I do think that having the mainstream representation of a culture being by someone of a dominant culture is still problematic. And by "problematic," I don't mean "morally bad" or "wrong" or "shouldn't be done," but just that there are a whole host of problems and questions involved, and that the issue is very complex and tangled.

Again, I think cultural appropriation is a really complex issue with no easy answers.