The release of WordPress 3.8 is planned for this thursday(12th of December) and it features a lot of new things, some more prominent than others.
Another part of the admin panel that has been reworked is the widget administration with much more focus on the available widgets, widget areas and less focus on inactive widgets.
More Clean Dashboard
Except for the obvious flattened design there’ve been some changes to the default widgets. For example news have been put together into one feed and the QuickPress has been simplified and renamed into Quick Draft.
A New Themes Experience
The theme manager has also been completely reworked, there’s more focus on the preview image and a live preview option if you wan’t to test how the site could look with your very own content.
If you click on one of the preview images you get to the more classic theme managing experience with all the information about the theme in a modal popup.