Cleaned up the existing tickets and organised them into a project for others to see what they can pick up - https://github.com/collective/plone.importexport/projects/7
I did some work on getting the tests working again and familiarising myself with the code for refactoring.
There was also some discussion in both the migration open space and on discord about the need for a more user friendly migration story that worked via the control panel. Even though plone.importexport tries to allow many uses not just migration, there was general agreement plone.importexport might be a good fit. In particular because it uses marshalling from plone.restapi internally. There will likely be a sprint on it in March.
Other usecases for plone.importexport are can include content reports, bulk metadata updates, bulk uploads of blobs, migrations or data sync from/to external systems, due to its use of a hybrid CSV, json, zip data format.