If a user does not use the default formats, then every single contact that is entered must then select all four of the new formats. This adds time to entry, and is prone to error. The person entering data must then go to the default format, and check to see if it is being used by any contacts. (if the default format was editable, this would not be required).
One way to do this may be to have "Formats" combinations, one of which would be default, and editable (or, if not editable, be able to select which combination is default). This would also allow the user to group Subject and Body formats, since if they are probably changing both, and not just one or the other. You could then have a new contact use the default combination, or select a different combination.
