Kohlberg stages of moral development

Yesterday in Nur356, we started to discuss ethics in nursing, including going over the six Kohlberg stages of moral development (good explanation here). These disturb me greatly. I'm not exactly sure why, but I think it's because they're so wishy-washy. The fact that Kohlberg (and others) can test people and fit them into these categories doesn't really tell you that much about them:

1. The theory does not take into consideration the interplay of different types of development in the life cycle. For example, we know from ADD that different parts of the brain can mature at different rates, resulting in different types of emotional responses. And we know that adolescents normally present with stage 3-like thinking--idealistic and so on. Do these emotional responses over-ride other cognitive styles of decision-making? Temporarily? This question leads to...
2. "Moral development" doesn't measure anything real. Is it a cognitive process, an emotional response? Does it have a place in the brain? Ideas about "goodness" involve all sorts of assumptions and beliefs about metaphysics, psychology, relationships. Kohlberg is making a way of measuring not a narrow development, but whole Weltanshauung. This leads to...
3. Kohlberg is arbitrary. Is it any surprise that the highest level of moral development corresponds to the type of political and philosophical outlook of people in Kohlberg's socio-economic circle in his time? This leads to...
4. Are there higher levels that Kohlberg couldn't measure because he couldn't understand them? If Level 6 isn't just a pretentious subset of one of the other levels, it is based on the idea of uniform dispersal of utility, which is based on an assumption of uniform value. Julius Evola might critique this by questioning, from a metaphysical perspective, uniform value. Charles Murray might critique this by questioning, from a biological perspective, uniform value. Some economists might critique this by questioning whether the self-effacing attitude implied at Level 6 actually leads to increased utility for all parties. They might also wonder about the free-rider problem...
5. How does an "immoral" person fit in? The Kohlberg stages are predicated on the notion that test subjects' reasoning will lead to a justification of "good" action. What about someone who says Heinz should follow the will-to-power? This person may be cognitively out of Levels I+II, but their reasoning seems to be like stage 2. How does Kohlberg deal with them?
6. How does game theory fit in? What if there's only a few doses of drug left and many Heinzs and wives?

Well, I would like to follow up on these questions more, but no time for that in nursing school. Actually, I think that, considering the shallowness with which these topics are covered in nursing school, they shouldn't be covered at all.