Thanks for the feature request. I’ll bring this to the developer’s attention.
Just as a note, I can see at least one reason why this is not already a feature. Everything depends on this field key.
If Elliot gave people the ability to change the field key they would then expect that changing the key would also change all of the rows in the postmeta and options tables as well so that no data was lost.
While I don’t think that allowing the field keys to be changed would be difficult; searching, finding and updating all the references to the field key would be a major project, and depending on the size of the site and the amount of db queries needed, it could potentially fail before it was completed.
~JH
