Well, since the Doak scale only rates the top half of courses, by his own system, then anything less than a 1 is still average, I guess. There could be 8,000 poor courses, but I don't think there are.
We could also define poor under the light of "poor for their audience." This group is only interested in the top 10% of courses in the world design wise, but a muni owner might look at his flat, bunkerless course, pumping rounds through like crap through a goose, as a thing of real beauty...…..