Drupal is a 'content' management system, not a 'page' management system.
Yet we continue to design static pages, to design to a pixel perfect 960gs.
Designing for the content is becoming more mainstream with things like Responsive Web design. And a page, pixel perfect design approach brings issues to implementing RWD themes.

How can we bring modularity to web design, how to make use of Drupal default elements, not design from scratch every time?

Have you managed to approach this issue? What are the solutions, styleguides? More emphasis on individual page elements being independent and reusable?

How do you help designers understand Drupal and CMSs in general?
What tools can you use to educate them?
How do you speed up and facilitate the Themer's job? Create communication and understanding between them and designers?