Was Britain's lack of additional light carriers early in the Second World War a major missed opportunity?
Short answerNot by itself. The deeper problem was the government's carrier-construction pause, and any extra ships would probably have been more useful as fleet carriers.
NotesAny proposed light carrier needs a realistic order and construction date. Removing the Second London Naval Treaty might have permitted more construction, but it would not remove the British government's decision to pause carrier building at the start of the war. If additional hulls had been authorized, full fleet carriers would probably have offered more value than deliberately small fleet designs. The missed opportunity lies in the procurement pause and the ships it prevented, rather than simply in the absence of a type called light carrier. This keeps the counterfactual tied to institutions, schedules, and resources.