For me, one of the key things that is needed is to extend the concept of Just Culture into the organisational context. Whilst there have been (some) improvements in the implementation of Just Culture to those at the pointy end of things, the process stops at those directly involved in the occurrence itself. If Just Culture, and all the other elements of culture that goes with it, was extended throughout the organisations involved in the causal factors hopefully the individuals making the decisions will feel more protected when they do things that are justified and with the best of intentions. Likewise, should anyone choose to do something less honourable, they would be aware that they were crossing a defined "line in the sand" for which they would be held accountable.
The challenge of course, would be for the MAA as the Regulator to enforce such a process and audit its application.