You are asking why all this should be codified. Why was the Charter of Rights and Freedoms created? The charter can be invoked in a good number of criminal cases. Is it invoked often? It exists, but our rights can be violated in a criminal trial. In case of reasonable doubt, the individual is acquitted.
This new bill will not fix everything. You are saying that no budget envelope is attached to it, but if there is a plea bargain, at least the victim will be informed. If it has been codified, crown prosecutors would know it, as would others. Mentalities will not change overnight.
When I was little, my father's friends would come home with a beer between their legs. That was 40 years ago.