"It has also been said on occasion that if the Lex had suffered hits in 1944 similar to those she sustained at Coral sea, she would easily have survived."
The US Navy had the very great advantage of having some reserve officers who were firefighters in civilian life. They introduced the USN to the latest fire fighting techniques, including the type of nozzle that produced a fine mist. The techniques and equipment went into use during WWII and provided the Navy with vastly superior fire fighting and damage control capabilities.
In the case of the USS Lexington if they had sent someone down to verify that the conditions in the generator compartment were suitable before turning off the nitrogen blanket the ship would not have suffered that massive explosion and would not have sunk. I would guess the USN implemented that policy very soon thereafter.
The largest displacement aircraft carrier in WWII, the IJN Shinano, built on a Yamato Class battleship hull, was lost due to the same problem. The USS Archerfish hit the Shinano with 6 torpedoes while it was on its maiden cruise, en-route to the PI with a load of the new Ohka bombs. But given the armor on that ship 6 torpedo hits was not that big of a problem. Satisfied that things were well in hand, the day after the attack the senior damage control officer turned over the job to a junior officer. The avgas tanks had been ruptured, filling the ship with fumes. The junior officer decided to get rid of the fumes by turning on the blowers; this created the world's biggest FAE. When it detonated that was the end of the ship.