Assign a new block to a region on add block page

From http://drupal.org/node/213085#comment-778083:

Another improvement that I would add to this is the ability to assign a new block to a region directly on admin/build/block/add (similarly to how one can assign a new CCK field to a fieldgroup on the field creation page).
The current workflow is:

1. Create the content for a new block at admin/build/block/add.
2. Submit the form, the user gets taken to the top of admin/build/block.
3. Scroll down to the bottom of the page (can be long) and try to find the block I just created in the "disabled" section.
4. Drag and drop or set region for my new block.
5. Scroll down to the save button and save changes.

Suggested:

1. Create the content for a new block at admin/build/block/add.
2. Choose region.
3. Submit.

skilip is currently working on this at the Drupal UX Sprint.