Documents should have privacy settings adjustable to role hierarchy.

This should be adjustable within organizational permission just like any other module. There are legal, transactional, technical, etc. documents that should be associated with an Account or Contact, but not viewable by anyone who has permission to view that Account or Contact.  A button could be added within Zoho to make a document public, but most organizations need to be able to manage the privacy of their documents, and Zoho's settings should mirror this.