Would swearing an oath to “Canada” rather than to “the Queen of Canada” not just bring us in line with the practice of other countries?
Almost no country in the world asks new citizens to swear an oath to the country. Republics for the most part require an oath be made to the constitution because the constitution is at least definable in law. Monarchies like Spain and Thailand have oaths to the King. Some countries require no oath or declaration at all from prospective citizens. France since the time of the French Revolution has had 2 kingdoms, 2 empires and 5 republics, and presumably there is not sufficient agreement about what should be in such an oath for it to have an oath of any kind. Even if that were not so, the idea should not be to make Canada like some other country but to have new citizens accept the unique character and heritage of Canada that are the source of everything that has made this country such a desirable place in which to live.