Why Force Z needed a carrier more than prestige

Could improved anti-aircraft equipment have saved Force Z?

Possibly, but carrier air cover would have mattered more, and the two-battleship deployment was strategically weaker than the planned carrier-and-cruiser posture.

Better anti-aircraft directors might have helped Prince of Wales and Repulse, but a carrier would have mattered more. British plans paired carriers and cruisers because aircraft supplied protection while cruisers threatened Japanese commerce. Two battleships advertised Britain's limited strength against a much larger Japanese battle fleet. Their deployment reflected prestige politics more than the earlier deterrence concept.