In 1992, the Department of Energy performed what may have been the most thoughtful and self-critical assessment of classification policy that any government agency has ever carried out. It is now available online.
“This study represents the first fundamental review of classification policy for nuclear weapons and nuclear weapon-related information since the Atomic Energy Act became law [in 1946],” wrote George L. McFadden, then-director of the DOE Office of Security Affairs, in a transmittal letter (pdf). It laid the foundation for the subsequent revision of specific classification practices in the 1995 Fundamental Classification Policy Review and other reforms.
The study asked basic questions — What is the purpose of classification (specifically, of nuclear weapons information)? What is wrong with the status quo? How can it be improved? — and then it considered various answers to these questions. Many of the questions, and a few of the answers, are still valid today. And the study as a whole remains impressive as a model for taking a “fresh look” at classification activity, especially at a time when the National Security Advisor is gathering recommendations for “a more fundamental transformation of the security classification system.”
The 1992 DOE study predated the world wide web, and as far as I know it has not previously been published online. A copy is now posted on the Federation of American Scientists web site. See “Classification Policy Study,” U.S. Department of Energy, July 4, 1992.