Could be useful, but I think there needs to be set rules, as we don't want to take this to an extreme. If we had a category for every single story in existence (e.g., Donald Gets Drafted characters or Christmas on Bear Mountain characters) we would have way too many categories. Instead, I think the categories should only apply to a particular series. For example, Donald Duck (Film Series) characters, Mickey Mouse (Film Series) characters, and Uncle Scrooge (Comic Book) characters. I'd probably recommend including Ducktales: Remastered characters in the DuckTales characters category instead of creating a separate category for Ducktales: Remastered, just for the sake of avoiding too many characters.
With all of that said, I could be wrong, but I think the admins prefer conversations like this to be brought to Discord instead of the "Discuss" tab on the Wiki. They can, of course, correct me if I'm wrong.