Removing editioning from an Oracle user
Based on Phil's test case I backed up the the production database using exp.

I dropped the editioned user, recreated them and imported the data with no issues.  The user had views and packages which were versioned but as long as you set the edition to the most current one you are good to go.

This query showed that the recreated user was not using editioning

SELECT username,editions_enabled
FROM   dba_users
WHERE editions_enabled = 'Y';