We are looking for the ability to mimic roles for API access, so that we can provide api access that only allows the same permissions as the Author role would use if manually publishing content through the Composer UI.
The use case would be in working with vendors to allow api access without giving them too much global control to publish or take other actions.
Thanks for the suggestion! This is something we'd like to add in the future, but at this time the scoping is limited to Application level.