Another use-case that wouldn't seem to be addressed by this implementation is that for crew/staff/writers/directors/supervisors/producers which takes a similar format but can be handled in a few different ways.
separate sections each of which have a different heading for the production team member's function
a single section with the function next to the episode.
Also, will there ever be a divergence in the implementation between {{Ep}} and {{Ep2}}? At the moment, they behave identically. you can put a season one episode into the season two template or vice versa and it'll output the same episode name link. I've found other wikias that implement the template as taking separate input parameters for season and for episode instead of a single input as is done here with the episode template on the expanse wikia.
The proposed {{Roles/S1 template would incorporate free-form values for the second column or any existing value in a predefined list: [producer, director, writer, ...]