trimpot - didn't any of this make the BASI/ATSB report?
The accident investigations aren't meant to finger blame, but they are supposed to identify changes to prevent future accidents.
Now it would probably be widely accepted that in this sort of case some of the recommendations would be on how to improve the regulatory system (a la Seaview, Air Ontario and all other such landmark investigations).
But one aspect of the authorities activity that is rarely considered is who they give licences to. Perhaps it is only a logical extension of accident/incident recommendations that in the extreme scenario that trimpot describes, the ATSB (as an example) recommend that CASA withdraw a person's licence (i.e. directly remove the hazard).
Now I don't expect that musing to be popular (even though it fits with the implications of other peoples postings quiet well), and I don't really like it myself because it would tend to influence the responses the investigators got and hinder the search for the truth. However it has a certain directness that we would expect the investigators to take when recommending (say) an AD to fix an aircraft defect.
PS: trimpot There is a recent Rotorheads thread on the British Crown Prosecution Service attempting a manslaughter prosecution after a fatal accident. Presumably a similar legal action could have be attempted independent of CASA by the state under Australian law in the case you describe?