I used to not mind the monarchy and would have preferred to keep it despite it being in opposition to some of my other views It played what I saw as a valuable role as historical referent point heritage and cultural and political continuity of Canada. It serves as a key reference point within the armed forces, and the rhetoric of "the Queen's uniform" and such still exists within the institution.
More important by far, it served as an integral component of our system of government both in function and symbolism. The neutral body of the Monarch and her representatives at the federal and provincial levels as head of state, served as devices which reminded us that politicians were at all times temporary creatures and could not amass regal powers and rule by decree. The custom of Royal Assent to legislation, the Speech from the Throne, the Black Rod and slamming of doors, served as poetic reminders of checks and challenges to power and ego inherent in politics. These are customs born of civil wars and times when monarchs were often tyrants and held a great deal more power than anyone should.
All that held until Stephen Harper and his band of subversives found themselves in office and began subverting the norms of our constitutional monarchy and parliamentary democracy of which the Queen was a feature. His quest to impose his own dark authoritarianism includes increasing the emphasis on the monarch as a distraction from his brutal insurgency against the mechanisms of government, and as saviour from challenges to it.
The militarism, fascism, and authoritarism with which Harper 'governs' is a mockery the monarchy and its role in our political system. I can find no further practical reason for the monarchy. I do not think, Harper or not, that our governance will be the same. The Queen's representative is revealed through prorogues to be open to abuse and bullying. The Queen and her children are abused as cynical baubles to distract the masses from other things. Parliament, and the separation of powers and the historical forging of a Westminster system are irrelevant under Harper because the inbuilt checks and balances have utterly failed.
In other words, under Harper, the symbolic role of the monarchy has increased (and cheapened!) while its practical role is systematically destroyed.
The door is open to a great many things and whether Harper has 30 years left or three, things will not be the same in this country. People are angry, times are uncertain, and wheels are turning. With things like Occupy, Carré Rouge, the resistance building to energy plans on the West Coast, there is a Revolutionary Consciousness building in this country. No, it is not universal and is often not explicit, but some things have happened that cannot be put back. These will have long term impacts on the politics and culture of Canada, whatever becomes of the place.