The bottom line is that you need to have the bow fit you . If its too short its wrong , if its too long its wrong . I disagree with Paul .I belive most archers can shoot a slightly longer draw bow much better than a slightly shorter bow . This is kind of a urban legand among archers that everyone would shoot better if they shot a inch shorter bow . Get the bow to fit you just right , youll be happyer , and shoot much better .

edit = To answer the original question I would say short is bad , will open up you groups left to right in most cases .