Previous to September 11th Canada was one of the few countries that allowed PAX to occupy the jumpseat. It has now followed in the paths of other contrives strictly prohibiting visits all together. In my opinion if a terrorist was determined to enter the cockpit he/she would find a way regardless of any laws or regulations.
When I started flying for the airlines my cockpit used to have 8 levers in the middle 5 dozen clocks in front and on the roof, countless swichtes, lights, handels, whees and knobs. The yokes housed en-route maps.
I think the automation and computerized flight decks will actually benefit the next generation of pilots, they are growing up in this so called "computer generation."