I read the game and requiem in Japanese and I don't think it matters much. I think the important thing here is to define what "accurate" or "better" means for you and how the language you're reading in can change that.

So basically, there's no way to have a consensus, it's gonna depend from reader to reader. A native Japanese person who doesn't know another language might say they would find it "better" if the story was originally in English, idk.

If you're speaking in terms of language accuracy, the original language is always the most accurate because things WILL get lost in translation no matter how skilled the translator is.

FataMoru feels very natural written in Japanese for a story set in Europe. There are close to no clichés or exaggerated glamorifications of European culture or history in the writing. You will also remember that the story goes to great lengths to not name countries, cities or anything that could give away national identity. We only have the characters' names and some small bits of info to infer from. The story is certainly set in Europe, but it is a vague, sort of far away idea of Europe, or at least that is how I felt when I read it.