Per the query in our just-ended teleconference, here are links to a sample of Use Case templates from across RDA groups. I think any of these would be fine for use in submitting new use cases to the Research Data Collections group, and welcome suggestions for others.  
The Metadata Directory WG provides a template at template https://rd-alliance.org/use-case-template.html-0 and example usage at  https://rd-alliance.org/use-case-example.html .
The Vocabulary Services Interest Group offers a slimmed down version of this template at https://docs.google.com/document/d/1siR-HAVKrJzpN3IVwyCMbsSNaCWu1eDtYdl4…
And for the Humanities Coordination Group we used this Data Convervancy template: https://rd-alliance.org/data-conservancy-use-case-template.html
You can also find an Use Cases group which provides aggregation of the various use cases submitted across RDA to-date: https://rd-alliance.org/groups/use-cases-group.html
 
Best.
Bridget