The scene appears to make one adjutant the admiral's sounding board, intelligence chief, operations chief, and practical deputy. That is too much information and responsibility for one officer to manage reliably. A real fleet headquarters distributes those functions among specialists who assemble reports, test assumptions, and turn an admiral's decisions into coordinated action. Their work also gives the commander engineering, intelligence, logistics, and operations advice before orders are issued. The comparison questions Starfleet's habit of using captains where a commodore or admiral and an established staff would normally be expected.
Chapter · 3:35-6:47
Why one Starfleet adjutant cannot replace a fleet staff
Sisko's appointment as Admiral Ross's adjutant opens a comparison with the intelligence, operations, engineering, and logistics specialists required to coordinate a fleet.