At any rate, the accident investigation is not a forensic investigation. The evidence obtained has not been gathered in the same way as that gathered for a prosecutor, and consequently a lot of it would be inadmissible. I'm not a lawyer, and I stand ready to be corrected on that point by someone with more knowledge about the topic than I.
Also, none of us, including that noted aviation expert Foreign Minister Downer, are privy to all the facts about the incident, so it's all conjecture about whether it was a case of gross negligence or not. I think it is shortsighted to look at the end result and conclude gross negligence is the only explanation. Was the crew fit to fly? Were they appropriately trained and experienced? Were they distracted or overloaded by other tasks? Was there sufficient overrun at the airport? Were there adequate emergency services available? Did they have the access they needed at the crash site?
But let's look at this from a purely safety based outcome - will stringing up the two blokes at the pointy end make an incident more or less likely to occur in the future?