My problem is that I indulge in writing sadistic comments on students' rough drafts, while I can't grade their final papers in the same way. Indeed, I imagine how much lighter the workload would become if I were exempt from giving letter grades to their final products. I do not deny the use of grading. But when you decide to study by your own will--ideally speaking, of course--when getting a good grade is not/ought not to be your absolute goal any longer, is there any point of quantifying quality in even an oblique way like A, B, C, and D? I feel that if the grading option becomes either pass or non-pass and we're instead required to assess the quality of student papers in longer and substantial comments, I'd embrace it very gladly: the material workload would probably increase, but the psychological stress should dramatically decrease, almost to zero.
