I think the first cornerstone would be to eliminate the arbitrary restrictions on when protection applies, so that it applies whenever you're not engaging in some sort of illegality by blowing the whistle. There shouldn't be artificial restrictions that it's written or oral, or that it's to a certain person and not another.
The second cornerstone would be to give whistle-blowers access to court if they don't get a timely ruling from the PSIC. In the United States, usually the cut-off is about 180 to 210 days. If your informal remedy hasn't produced results by then, you're free to go to the next step and graduate to a due process remedy.
The third cornerstone for improvement would be getting in the modern burdens of proof that are part of the best practices for every recent national intergovernmental whistle-blower law.
The fourth cornerstone would be adding in the premise that you will be “made whole” if you prevail in your whistle-blower retaliation case so that you're not worse off even though you've won.
You can add all four of those premises without dismantling the portions of the law that are currently in existence.