Well, the sites that used to do it took their sweet time (like a thousand years, right Mare? LOL), so I don't think that would be a problem. But if course, if you allow a month per story, you'd get really backed up unless there were a lot of reviewers. And if there were a lot of reviewers, it would be harder to compare stories to each other objectively based on reviews, cause everyone would rate a little different.
But maybe we could have one reviewer per genre (maybe two for the more popular genres on AC), and that way at least stories could be compared within their genre. And also, reviewers could just read stories in a genre they like. (So Mare, no romance for you! LOL)