How Hornby might have performed in a major war

Would Hornby have been remembered as one of Britain's greatest admirals if he had fought a major war?

Probably: his seamanship, fleet control, and management of difficult subordinates suggest that he would have performed very well in major command.

Any judgement of Hornby's wartime ability is necessarily counterfactual because he never received the major fleet battle that would settle his public reputation. His observable command qualities included diligence at sea, control of fleet movements, and the ability to make disparate personalities work together. Those strengths mattered in war as well as diplomacy because a fleet commander had to coordinate ships and senior officers under pressure. His crisis management can therefore be assessed as professional command rather than mere political luck.