Good points Bill. I think that selecting good content is contextual, based on a variety of factors such as location, learner needs, and teacher skills & knowledge. That is why I am against subject/content curriculum that is decided far from the learning process.

Recommendations for subject material (such as Piaget in your excellent example) would be of assistance to the learning process. "Recommendations" for content are different than a curriculum based primarily on content, and from which the teachers must teach and the learners must conform.

I agree, good content should not be overlooked, but who decides on what is good or appropriate content? Does the learner have a say, or just the experts?

One thing is certain, we're not going to solve all curriculum issues on this blog ;-)