I'm not sure if this would even be possible, but it would be awesome to be able to restrict the visibility of tables to different Active Directory security/user groups. For example;
Main user group - can only view "Products" and "Clients" tables.
Super user group - can view "Products, "Clients", "Staff" and "Payroll" tables.
Accounts user group - can only view "Payroll" and "Staff" tables.
The current option of hiding certain table's relationships is fantastic, as well as the option of assigning a different group for "Admin" level access and "User" level access, but having that level of control over specific tables as well would be great.