The Japanese did not have a distinct edge at Coral Sea.
The 17 G4M Betty bombers that attacked USS Lexington as she attempted to attack Rabaul were slaughtered. Only two survived the initial attacks, and one of those would crash land on the way back to base.
Of course, when you are facing little opposition, things tend to go your own way...Such as the early American carrier raids.
An unescorted bomber strike is more an exception to the rule, they usually fared badly, though there were exceptions, especially against the poorly armed Italian and Japanese fighters, when it comes to shooting down bombers firepower is all important and only the A6M, of all early war Japanese fighters, had a decent armament (and IIRC very much by chance as the factory that was originally planned to produce the 20mm for it was taken over by the Army). Up to mid 1942 the Japanese could achieve local air superiority, then they got involved in an attrition campaign that required their planes to fly at the limit of their endurance and things turned against them a they could not sustain that sort of losses..