Come and think of this, this could also be tied in to the continuing discussion on reviewers' styles, not that I would ever do that, right?
Style and voice seem crucial to a short story but are easily turned into abstractions.
Style has become a bucket of worms, thanks to the deteriorating standards of the public schools. The chief style I see in student stories is American Illiterate. It shows up in published stories sometimes too. "Should an enemy warrior cross that line, kill them!" Well, that's okay if the order-giver is an illiterate. Unfortunately, the illiterate is just about always the author. Other than that, the style should suit the story. Imagine The Wings of the Dove as told by Huck Finn. It would be funny for ten pages, but...
If you're asking about the author's voice, or the narrator's, it's so closely linked to style that I see no point in discussing it separately. If you mean the voice in which each character speaks, each must be different. The butler mustn't sound like the footman, even though neither is an important character. This is one of those truths that students reject out of hand. They reject it because everybody sounds alike.
Considering that I just finished my second day of in-service training today, funny how Wolfe's statements dovetail nicely with what high school English teachers have said for years about student writing and comprehension of literature. But I suppose some might disagree with this assessment and with Wolfe's comments. Perhaps someone reading this has something to say?