[Suzerain of Sheol]

Actually, you just reminded me of this -- command of the language is another thing that doesn't earn you any points as a writer, it just puts you at the baseline. If the actual text shows signs that the author doesn't fully understand the conventions of their own language (or even the definitions and connotations of the words they're using) then that severely tarnishes, if not outright obliterates, any other good qualities the story might possess on its own. A story has to be readable to be good -- if the reader gets thrown out of the narrative time and again because of mistakes or improperly-used words, there's no way they can enjoy the story, or even focus on it.

Also, I'm on the opposite spectrum. I'm an English major and a writer, myself, so I tend to obsess over things like sentence structure and word choice. I'd be hopeless at reading a text in another language, though. :p