I think you are very much on the mark. And the last thing we need is a head of state that lasts for life time, from a foreign government. I, actually, do not understand how Canadians, whom I respect, very much would have a head of state who is not Canadian. Monarch are good and bad, Queen Victoria was a selfish woman who lived a very long time. The average American would like no part of monarchy.
First of all, the head of state of Canada is a Canadian. She may not have been born in Canada or lived in Canada, but her position as the head of state of Canada and the head of the Canadian royal family makes her Canadian. In Canada, unlike in the US, we don't hold any fears about our head of state, political leaders, etc, being foreign born. You would never see a Canadian election focus on where a politician was born or demands to see a Prime Minister or Governor General's birth certificate. In fact, while our current Governor General was born and raised in Canada, the two immediately prior to him - Adrienne Clarkson and Michaëlle Jean were both women who came to Canada as refugees when they were children; Clarkson from Hong Kong at about age 2, and Jean from Haiti at about age 11. This isn't to say that we necessarily have better things to argue about when it comes to our politicians, but rather that we have different focuses - where they're born isn't an issue so much as whether or not they speak English and French, and if they're from Quebec whether or not they're separatists.
As to the idea that "Monarch are good and bad, Queen Victoria was a selfish woman who lived a very long time," as you put it, I think you're missing a very important point here. Yes, monarchs can be good, and yes they can be bad, but you're failing to realize how much, or rather how little, real power the monarch is able to wield. Queen Victoria was a selfish woman who lived a very long time, and in her life the British Empire prospered. For some time prior to her reign, but even more so during it, the monarch had been transitioning into becoming a symbol representing the people, the history, the culture, and the traditions of a realm than an actual source of power. The monarch's role is not really to rule so much as to represent.
The Queen said, in 1973, "I want the Crown to be seen as a symbol of national sovereignty belonging to all. It is not only a link between Commonwealth nations, but between Canadian citizens of every national origin and ancestry [….] I want the Crown in Canada to represent everything that is best and most admired in the Canadian ideal. I will continue to make it so during my lifetime. I hope you will all continue to give me your help in this task."
I think this could probably be applied to every realm, but it hasn't always worked out that way. Some people and some realms no longer feel that the Queen really represents them, and that is their right. I could see a point when Canada begins to see things that way - while I think the Queen raised her children to have a strong sense of the Commonwealth, I'm not always convinced that the message has been passed on to William and Harry, which won't serve the Commonwealth well in the next generation. That said, the monarch has representatives in Canada, and just how well the monarchy represents Canada depends on those people as much, if not more so, than the actual royal family. Personally, I think the last three GGs of Canada have done a rather good job of representing both Canada and the Queen - at times, even better than the Prime Minister, although I will admit a bias in that regards as I don't have a particularly high opinion of our current PM.
Henry Jackman, former Lieutenant Governor of Ontario said "For the monarchy is much more than a person. It embodies the constitutional framework of our freedoms, the set of beliefs and attitudes of tolerance that make up this great country and make it distinctive. The Queen is the symbol of what we are today and the history of which we are the result and which is part of us. If Canada were to abolish the monarchy we would be abolishing the symbol of our distinctiveness."