Current behavior: If a Custom role is created with the content library edit all content permission, the user will not be able to access the full list of reviewers under All content until the content library setting option is enabled under Org settings, as shown in the screenshot below.
Expected behavior: To have list of reviewers to be seen when Edit all permission is given.
Discussed with Viswanathan who created a story on this and S4 is also raised for the same.