I’m planning to use discourse for all educational courses within a program, as well as to host multiple research groups. Both approaches promote course = top level category + multiple groups (course team and course participants), or research group = top level category + discourse group. Both don’t map naturally on multiple isolated discourses. The educational program has the same cohort of students. The research groups are typically too small for a complete discourse instance and benefit from shared knowledge.
On the other hand, in both cases I want to delegate a significant amount of autonomy: course instructors will want to arrange their courses in different ways, and research groups will want to create subcategories for research projects.
It seems that both needs are best addressed by an ability to delegate the power to configure the top level category and groups. A possibility would be to have a higher permissions tier “manage” to categories and subcategories. This would also parallel how group owners can manage their groups.