About a year ago, Carl and I were doing a training in Washington DC. When we got to teaching Drupal themes to a bunch of qualified people with HTML, CSS and some PHP knowledge, we listened to our own explanations, looked at each other, and both thought "it shouldn't have to be this complicated!" Drupal 6 theme development was different than Drupal 5, and Drupal themes in general were still a beast unlike anything else, but with a little explanation, people got it, and people learned to appreciate Drupal 6 theme development rather quickly.