Today the export/import function of new customized/edited roles are very limited in D365.
If you have made some new roles in a test environment and you want one or more of those roles imported into a prod environment, you would get all edited/customized roles from test into the prod environment. You cannot select which one you want to import. After import you need to delete some of the roles you did not want to import.
Another issue occurs when one or more of the new/edited roles from the test environment got the same name as one or more of the roles in the prod environment, the import of roles will fail. Then you need to delete the role(s) with the same names in the prod environment and then do a new import and then all edited roles from test will be imported into prod environment.
The fixes that should be made:
1. Should be able to mark the roles you want to export/import to another environment and only export/import those.
2. Should be able to change the name of a role when importing/or that D365 adds a number/letter/word automatically behind the name of the role you are trying to import (if duplicate name).