Garland, these are interesting observations. I agree with Huck that a great course should be playable for beginners and average players but challenging for excellent players. By this measure, I think all the Bandon courses are doing great, so it may not be fair split hairs between them.
I can see why Old MacDonald would score so well on the Huckaby meter. The fairways are wide open, it's hard to lose a ball, and it's hard to make a big number. However, the green complexes are so nasty that it would be hard for even the best of players to make birdies.
To some extent, I would have predicted Bandon Dunes to be the worst by this measure. I think it's a lot easier to make birdies out there because the holes (and greens in particular) tend to be more straightforward. On the other hand, there's a lot of trouble and the potential to make big numbers. Nonetheless, BD is much better than the average course by this measure so it's not fair to call it "the worst."
I'm not sure that the ratings are reliable, but can you show these scores for some other well-known courses to give us some points of comparison?