While not having word limit may spin creative webs to some writers, it may also completely sink down the drain. I think that with any writing contests, a word count limit and theme are almost a necessity - not to hinder the creative minds of our writers, but to keep things balanced between writers and readers / judges. I don't know much about writing, but that's the general gist I get just by observing other writing competitions. Monthly is probably not enough time too. So bi-monthly or every 3 months?