Even if he had taken launch codes (which I don't for a second believe he did), you're telling me they don't change those between presidents and every few months? Anything he could have taken should be useless by now.
They make me change my password at work every three months and all I can do is read the employee newsletter and check my schedule. You're telling me they're less careful with launch codes?
It's clearly something else. Most likely information damaging, or even incriminating, of people currently in positions of authority.