This is yet another hurdle to publication that authors have no control over. :(
As editors, we want to have a well-balanced issue with a variety of types of stories. So, if we have six awesome vampire stories in the hold-for-voting pile, sadly, only one is going to make it into the issue.
What does this mean for authors? This means if your story is about something unusual, something others aren't writing about, you'll have a better chance at publication.
I look forward to seeing those unusual stories in the future!