I theeeenk I know part of the solution to the problem. CASA was set up as a statutory corporation or suchlike. That meant that its employees are quasi public servants but not subject to the same discipines as true public servants.
This has allowed CASA to play fast and loose with both the government and aviaton community. When it suits them, they are public servants with all sorts of statutory jackboot powers, but without the straightjacket the public service act imposes on such persons.
When it suits them they are a corporation, free as air to do what they like including engaging in investigation and litigation techniques forbidden to the public service and police forces around the nation.
This is the classic "run with the hare and hunt with the hounds" situation. To put that another way, try sidling off to Montreal for a conference if you are a real public servant, the approvals process will generate half an inch thickness of paper.
The solution then is to abolish CASA, which can happen overnight. Allocate the regulation activities to a unit of the department of transport (or a ministry of aviation) and enforcement to a unit of the AFP.
This solution breaks the alleged "iron ring". If we then adopt the NZ FAA regulations and add a requirement that the regulations are to foster aviation, the job is done.