To avoid arbitrary decisions, you have to have rules of the game for how much evidence it takes to win and to prove your charges.
Right now, Canada's law is one of the few in the world that don't have any standards for what it takes to prove retaliation. Those standards have been very well developed over the decades. The European Union directive and the United States standards are pretty much equivalent to each other. I think the EU burdens of proof are a little more cleanly written. The U.S. ones have some idiosyncrasies for our legal system.
Without burdens of proof, a whistle-blower is at the mercy of the whims of any decision-maker. That means the rights are totally dependent on subjective factors, rather than objective, credible factors grounded in the public interest.