In his brief tenure as AFL Commissioner he encouraged owners to aggressively pursue NFL stars and also helped convince 3 NFL teams (Cleveland, Pittsburgh, Baltimore) to jump from the NFL to the upstart AFL which led to the merger.
That's not exactly how it happened. Those three teams moved to the AFC after the merger to balance out the conferences.
Al Davis did know the game in his day. He could take retreads and has-beens and make them work in a system. Jim Plunkett was a wash out and he won two Super Bowls with the Raiders. Al did have a tendency to overdraft speed. The fastest guy in the world won't help if he can't catch the ball. But he did love the deep passing game.