Cannot Change Issue Type to a Different but Compatible Workflow

For one of our projects, I have created two custom workflows, Simple and Testing. The Testing workflow scheme is a superset of the Simple workflow. The Testing workflow is associated with a Test Task issue type and Testing Activity sub issue type. Now the project manager wants to migrate certain existing Tasks and Sub-Tasks to the new issue task in order to take advantage of the new workflow.

Based on JRA-10167 and JRA-11229, Jira does not allow issue type changes when the workflow changes. However, this brute force solution to the original problems does not allow us to do what we want now.

My expectation is that Jira should allow issue type changes across all issue types. When the issue current Status is available in the destination issue type workflow only once then the migration to the new workflow can happen without intervention. If the status is available more than once (creating ambiguity) or not at all (creating an orphan) then Jira should prompt for how to map the states.

Similar behaviour should apply to bulk changes.

In the meantime we do have the option of creating a new workflow scheme with all issue types in the same workflow, migrating the project to that scheme, moving all the issue types we want and migrating the workflow scheme back. But this is a pretty painful workaround and I can guarantee that in the future some issue will be created with the wrong issue type and this workaround is too painful for regular use on a project with over a thousand issues on the go.