@jbielecki
When using the new/updated "Files" interface and accessing the "Files" area from the "Account > Files" area, the root of the "Files" area only supports sorting by name.
If you go into the one of those folders, whether it be "My Files" (which by default, is at the top) or another folder (which the list contains the names of courses that you have access to), you shoud be able to sort by the different column headers (such as "Name", "Created", "Last Modified", "Modified By", and "Size").
Based on the screenshot that you have provided, you are at the root of "Account > Files" area. Have you tried going into any of the folders and then sort?
-Doug