According to John Keegan (Intell in war) Intell has never determined the outcome of a battle - it is brute force that is the key!
I have read Keegan's Face of Battle, the History of Warfare, and several articles by him and have the greatest respect for his knowledge, but I would really like the context of the statement you attribute to him. I doubt if he would minimize intelligence that way. The US broke the Japanese Purple Code and the Brits the German code (Enigma). I can't imagine what would have happened if we did not have that information. Knowing the enemy's plan of battle is an immense advantage.
Midway.