OK, back to the question. I accept (because I had dealings with some of those VSOs named by tucumseh) that those major investigations were corrupted.
That doesn't mean the BoI system is flawed. It means flawed individuals corrupted it. We do not throw out democracy because it resulted in Hitler, or Mugabe.
Minor BoIs do not attract this kind of influence, so police involvement should not be automatic, as it is now, interfering with or delaying the technical inquiry. There should be some kind of threshold for police involvement. You clever people might like to suggest what that threshold should be. How about the result of the technical investigation being submitted to a judge or coroner after the first RO, say? I'm sure you'll all have better ideas, let's hear them.