I'm starting to get involved with Drupal administration redesign. Following Kristjan's usability suggestions, I proposed that I would do a heuristic evaluation of Drupal Admin to see if he missed anything and to organize/present his suggestions by usability principles. Unfortunately I haven't had time to complete that because it's a crazy time of year. I've been making small suggestions, however, and since Dries went and implemented some of Kristjan's suggestions, I made some proposals with wireframes:

Layout:
* The breadcrumbs are great. Is there any reason why we can't still see the
list of navigation options in a left column as well?
* A link to the home page is missing
* Here is a wireframe of proposed layout:
admin_layout_1-0.jpg

Doing it in CSS:
* We could use a strategy where we use CSS positioning to layout the admin
pages. We would create misc/admin.css and include it with admin.php pages.
We would surround 3 areas of code with div id's (see wireframe below for
illustration). This way, some layout can be controlled by the user with CSS.
* Here's a wireframe of proposed css strategy
admin_css_1-0.jpg