I think the roles of the regulator (CASA) and the investigator (ATSB) are sometimes misunderstood and conflated by some. It is not the ATSB's remit to 'point a finger' at a person and state the need for prosecution. They set out the facts and they are (usually) careful to look for systemic issues (as well as personal contributory actions). The report itself cannot be used in a court of law.
In this incident, they were criticised for not making enough of some of the systemic issues so they went back, with a different group of investigators, and redid it. The aircraft was recovered and the recorders interrogated. They added quite a bit (I thought) to the context but not much to the story. The newly-added recorder data did little to help the outcome for the captain. He might have been better-served if NGV had remained on the seabed.
The ATSB's investigations are intended to illuminate both failings and failures, and their reports highlight 'What we found' and include recommendations that are predicated on preventing a recurrence. They try to keep emotion and emotive content out of it. It is not their job to ruminate on the hurt feelings or egos of individuals or corporations.
I acknowledge they sometimes take a long time to finish a report, but it has to be understood that in recent years they have had the devil's own job securing a sufficient budget to retain personnel numbers.
Their draft reports go out to all who were involved and they consider all feedback in an effort to ensure factual accuracy in the final report.
CASA may be another story. It is a matter of personal concern to me that in the transport accident investigation space in Australia (various modalities) there is excessive staff cross-pollination between regulators and investigators. Senior bureaucrats inevitably become 'politicians' and I believe political networks have a lot to answer to in the organisational performance that we might be inclined to criticise. The troops, I suspect, work hard to do the job effectively and professionally. It's too bad that public service salaries (at the investigator level) can't match those for experienced airline pilots. Having to live in Canberra probably holds them back too.