The G3 was expected to operate more independently, so its design had to survive encounters without immediate support. Lexington was conceived as a reconnaissance element for a larger American battle fleet. A hostile ship meeting Lexington would therefore risk the arrival of the fleet's heavier force, changing the acceptable design tradeoffs.
Notable Point · 41:23-42:08
G3 and Lexington were designed for different fleet jobs
Comparing the ships one-for-one misses the British independent-operation role and the American scouting role ahead of a battle fleet.