Ways do exist to make longer papers better. Rarely are adults asked to compose essays and articles about unfamiliar subjects. We write about subjects we know well and those we care about. Students, however, must often write about subjects they understand only vaguely if at all. In many instances, students fear writing because the task is little more than a test.
Longer papers are a double-barreled threat.
They are not sure of the subject matter and they aren't sure of themselves as writers. Improving writing means helping students feel more confident about both subject matter and writing. During one English course for college freshmen, students selected a subject of personal interest and pursued that single subject through the writing of at least three papers an interior monologue, an interview, and a memoir. They explored the subject from several different perspectives. However, by continuing to use the same subject matter for three papers, they were able to focus more attention on writing effectively which, of course, was the goal of the course.