Instruction is a field that has been extensively researched. Over the last 25 years, theories like Cognitive Load Theory, Multimedia Learning Theory, and Elaboration Theory have emerged, which have improved learner performance by applying a specific set of principles for information presentation. Drs. Jeroen J.G. van Merrienboer, Paul Kirschner, and their colleagues in the Netherlands conducted scientific research that synthesized many of these theories into a whole-task model of Instructional Design. Applications of their Four-Component Instructional Design (4C/ID) model have been shown to cause improvements in transfer performance for a variety of complex skills.
I believe that by applying the systematic approach to problem solving prescribed in the book, Ten Steps to Complex Learning: A Systematic Approach to Four-Component Instructional Design to training for Drupal, the community will increase the likelihood that a download turns into a site, and that an intern turns into a competent developer.