One thing that comes to mind for me is - would there ever be a reason a user would need to add a field manually that is not part of the template?  An example from personal experience is where when the original template was built, the customer did not want a generic "comments" field added to the template.  However one of the staff who has worked with other templates in Laserfiche ran across a time when they really needed to add a "reference" comment about the document.  So they clicked the Add/Remove fields button and added the comment field to that document's metadata.