I'm not sure what you mean, although I agree that forcing a redundancy will quickly undermine any proposed structure. I'm not proposing separate categories that mean the same thing. It's more about how to name a category so it can encompass a broad range of sub-categories. An example is Category:Schools, colleges, institutions or Category:Subjects and topics.
I've made a first proposal for these top categories at Workgroup:Categories/Proposed_map. Maybe you could provide an example of the redundancy using one of the elements in this proposal.