It would be nice if one could filter all native Joomla content fields by excluding certain (groups of) values from the selection. For example: Access is a native Joomla field who contains all the defined Access Levels. I want a user to be able to choose only a few of them.
Practical example:
Add an additional text field to the Access field in the F2C Content Type and exclude the values entered in that field in the select statement which populates the Access field in the F2C article manager.