Which modern warship system would make little sense on designs from earlier decades?
Short answerA full modern electronic-warfare suite, because optical fire control dominated before relevant electronic threats existed.
NotesWarship requirements only make sense against the technologies an opponent can actually field. In the 1920s and much of the 1940s, optical systems dominate fire control. A modern suite built to detect, deceive and jam electronic emitters would therefore have few relevant targets. The comparison shows why transferring a present-day specification backward can add weight and complexity without adding period combat value.