There are fields in Jira (and I imagine other integrated applications) that don't map cleanly to an Aha custom field type. I am proposing a new custom field type that is an always-readonly text field that can be mapped to any Jira field type, and when mapped, the integration can only be one way Jira-->Aha.
Our use case is we have an "engineering owner" user field on epics in Jira, and we have Jira epics mapped to Aha features in the integration. It would be great to see who the eng owner is on a given Aha feature once it's been linked to a Jira epic. The catch is that many of our engineers won't have Aha accounts, so we can't easily use the traditional user fields mapping. And right now if you create a simple text custom field in Aha, you can't map that field to a Jira user-type field, presumably because the types don't match. So, it would be great to be able to send the selected Jira user's name (and/or email address) back to Aha once assigned.
I can imagine many other uses of this approach where Jira field values aren't easily mapped, but it would be useful to see a read-only text copy of that value in Aha.