Is this what you mean? I don't think there is much value in making the target...

Is this what you mean? I don't think there is much value in making the target configurable as well. Actually, I am not sure when this would be used. It seems we are migrating data from a source outside Drupal to a table outside Drupal with Drupal in between but I realize there might be edge cases, and there is no harm in adding this (it's optional anyway)