The new layout of Categories is nice, but the biggest new functionality is what you can do with them. Categories can be moved. So if you don't like having them located where they currently are, it can be adjusted more easily than before.
There is now Bulk Action for Categories, this will allow you to do a few different things. In the image below you can see how to perform the Bulk Actions. You check off the categories that you want to effect, and then click the Bulk Actions button and you'll get the drop down as seen below:
The bulk actions list are pretty simple. You can activate and inactivate categories in bulk. So if you have areas of the book that don't pertain to the work that your company does you can inactivate those Categories.