My take is that it's more of a "tiered" thing. Outside of the top 5 or so classes, I think you start getting "diminishing returns" fairly quickly on that ranking. A top 5 class is better, by a long shot, than the number 11 class. But is the number 11 class really that much better than the number 17 class? Probably difficult to know most years. I think there are a lot of groups of classes that are probably very similar, so the actual ranking doesn't mean much. If you have the 40th or 60th class, they both suck pretty bad, so who cares at that point?

Tier 1 - Top 5
Tier 2 - 6 thru 12 or so
Tier 3 - 13th thru 20th or so

And so on...