So writing, which has the description For questions specifically related to written English., has been applied to many questions and very few of them are specifically focused on written English.
It's not a good tag, but changing the name to "written-english" would make it more obvious what the intended use of the tag is and it would mirror spoken-english. After looking at the questions tagged with writing, I thought maybe it should be black listed, but I don't feel strongly about it.
We discussed this a few years ago in What should we put in [writing]? but there was no real consensus, so I'm bringing it up again.