I think that ultimately you run into the same issue.

In US education you are taught that you need to get an A. Anything below a C, gets you on the equivalent of a “Performance Improvement Plan” in corporate world. And B is… well… B.

So with that rating engrained, people would probably feel bad about rating their ride-share driver a C when they did what was expected. And it wouldn’t stop companies from pushing for A ratings.

Even elsewhere like the food industry where they do have letter ratings, A is the norm with anything lower being an outlier.

Perhaps for this to work, it would need a complete systemic shift where C truly is the average and A and F are the outliers. In school C would need to be “did the student do the assignment.” And A would need to be “the student did the assignment, and then some.”

There's nothing intrinsically intuitive about letter grades. It's just that you've been taught those specific arbitrary mappings.

Consider for example the "S" as a better grade than "A", originating from Japan but widely applied in gaming.

Even worse, is S actually good, or does the scale go SSS+, SSS, SS, S, A, B?

We'd still get the same pressure to give an A+ to every interaction unless things were fucked.

I used to rate three stars for what "performs as expected" until I realized that it's punishing good products. Switch to A-F would result in the same behavior, except it'd be Uber drivers trying to make a living instead of noxious parents declaring that their kid deserves an A.