Mmm... I'd probably want stuff to not disappear from new/recent posts, even if voted down. Instead, let them fall out of the popular (and fall lower in the promoted list, if a promoted one ended up being voted down that much)

ie, to me, new/recently posted means just that, a non filtering list of simply "what was posted recently", while things like "popular" and so on are more appropriate places for such filtering to occur.