This essentially guaranteed everyone an A in the course, if they did the work. But the focus was on getting you to improve your writing, not to fail people out. My opinion is that this is how writing should be taught, rather than giving you one shot to get a grade.
(I also once had a writing teacher who gave me a zero for a paper because it wasn't submitted in a manilla folder, and no late submissions were accepted, so I had no chance to fix it.)