==Long Range at the expense of Armor Protection== 

 The "cup is half empty" capitalizes on the lack of armor protection for the pilot.  The "cup is half full" emphasizes the reason why the A6M lacked armor: It was designed for long range.   From about 1940 thru 1943 the A6M had nearly double the flying range of an ME109 or British Spitfire.  And more than any other single engine fighter until the advent of the P47s and P51s.  Additionally, no pilot armor could withstand the impact of an American .50 Browning machine gun bullet!  So long range was far more important than adding armor that would not stop a .50 caliber bullet anyway.