Speaking with people involved in the Ontario school system, I was surprised to learn that they do not have provincial exams for courses in the last years of high school. To me, this seems like a mistake. Provincial exams provide vital information to university application departments: specifically, they let you gauge how much grade inflation is happening at any particular school. A school where the mean class mark is 90%, but where the mean provincial mark is 60%, is clearly inflating grades. Conversely, a school where the mean class grade is 60% but where students get 90% on the provincial exam clearly has high standards.
Given that individual schools and teachers have a strong incentive to inflate the grades of their students, provincial (or federal) exams seem to be a key mechanism for keeping them honest. Otherwise, there is simply far too much opportunity to call mediocrity excellence, without anyone else being the wiser.
I very much hope B.C. retains the provincial exam system, and that it becomes universal across Canada.