When it comes to public transport with a lot of people on board, no matter a plane, train or bus, it is up to the company and authorities to minimise the chance of a disaster, and that's why there is rules. For instance drink checks on trains (checking blood of driver), ect.
From this Germanwings disaster, the new rules implimented (hopefully worldwide) will be 'always two in the cockpit', also further scrutiny of pilots mentality and lifestyles will have to watched. It should go with the job, as pilots can be under a lot of stress.
It does not remove the chance entirely of another suicide pilot going into the ground, as they could knock out second person if desperate enough, but it does cut the risks down.
When it comes to it, we the public are in the Pilots hands, like it or not.