Right now Mp3tag provides us with an option for clearing of fields. You choose "Remove fields" from the "Select action type" drop down list and you can list fields that you want to remove [clear them of any data]. We can even do the opposite and choose not to remove certain fields while wiping completely all out the remaining ones
How about a similar action for switching fields? If the user want the field A become B and B have the content of A, then a simple action like this can do the trick: Format value "TEMPORARY": "%A%"
Format value "A": "%B%" Format value "B": "%TEMPORARY%" Format value "TEMPORARY": $char(0)
It is clean, it is simple and it works. But also cleaning a single field is simple [it only takes a >>$char(0)<<]- and yet we have not one but two versions of action types for this task. And why? Because it saves us time in the long run
This new type of action that I am proposing would simply have two fields to fill in- with [in my example] literally "A" and "B". And that would be it- you could not possible make this even more cleaner and / or simpler