I may be missing something but this "Thai national with a Muslim sounding name with less than six weeks in the company" will still have access to the cockpit. They will still stand next to the axe each and every time they do gain access the other multitude of times they normally would throughout any given flight.
What is different about their entry into the flight deck when a pilot needs a wee, to their entry when a pilot receives their lunch? If they are a terrorist they have still gained access.
I believe the German pilot would not have carried out his murderous intentions if a FA had been on that flight deck with him.