Why an all-fighter HMS Hermes was not the ideal answer

Was HMS Hermes ever considered for an all-fighter air group?

Yes, but as a cruiser carrier she was generally better served by Swordfish-type reconnaissance and strike aircraft.

Hermes was considered for an all-fighter group and at times carried fighters, including Gladiators. That loadout could strengthen local air defense but would consume the limited capacity of a small carrier. In her cruiser-carrier role, Swordfish or comparable aircraft supplied reconnaissance, torpedo attack, and reach against surface threats. The better air group depended on the mission because trade protection needed more than fighters even in a theater exposed to Japanese aviation.