Fighters are great things to have; especially if yours are better than theirs. They allow you to more effectively protect your fleet, ride shotgun for your strike forces, strafe the bad guys, etc. While there are certainly exceptions, as a very general rule, they don't do as good a job of sinking the bad guys as do your strike craft. I don't know that there was a single aircraft that was the deciding factor for the Allies in the Pacific. However, if one accepts the notion that there was such an entity, I don't know that one could make a better argument than the Dauntless.