I would consider inadequate design of the pressurization system by the manufacturer to have been a significant contributing factor here. Similar in consequence to the inadequately designed AT retard function which contributed to bringing down THY 1951 at Schipho
It must be so frustrating and difficult for any aircraft manufacturer to be forced to try and cover every possible eventuality that incompetent pilots get themselves into. The Turkish Airlines accident is a classic example where the crew apparently just watched in disbelief at what was occuring in front of their noses - and did nothing...
The Helios accident is another case in point. After this accident, Boeing had little choice but to once more grit their teeth and try to cover their arse by acting on the Accident Board recommendation that a specific checklist of the position of the engine bleed switches, the pack switches and the Isolation switch should be made - even though for many years the original checklist items were considered sufficient to be understood by competent pilots.
Despite that, my private view was that the after takeoff checklist should always have been subject to the usual challenge by one pilot and answered by the other. Yet there was no mention by the investigators of the Helios accident of that flaw (my words) in that specific checklist policy favoured by Boeing since the very first 737 flew.
No doubt, former flight engineers could make the point that if an F/E had been carried as a member of the operating crew, the Helios event would most likely have never happened. They may well be right. But that doesn't necessarily mean Boeing should redesign the flight deck to include an engineer in future Boeing aircraft designs.
Plugging perceived loop-holes is never-ending because there will always be slack incompetent pilots on airline flight decks who will find a way of stuffing up somewhere. Maybe not today or tomorrow - but one dark night...