Agreed. The changes towards modernism and diversity are part of the history of the twentieth-century in Toronto and Canada, the depression/war years being the watershed events that set us on this new course. My growing assessment, however, is that while modernism and diversity have been good, Multiculturalism was reactionary and harmful to a maturing understanding of ourselves and to the understanding that we would project to newcomers who adopt Canada as their home.
Multiculturalism came about in a time when we discovered that the official history, the official culture, etc. was an insufficient description of Canada
as it existed then. Canada has always been a multicultural country, much more so than many people realize, and that multiculturalism is not solely a product of recent immigrants but of communities that have been here longer than Canada itself: Aboriginal peoples, Acadians and other Francophone communities outside of Quebec, Cape Breton's Scottish community, a disctinctively Newfoundlander culture, etc. No idea of a monocultural or bicultural Canada could exist without systematically excluding these communities, so we decided it would be in everyone's best interest to celebrate our differences instead of glossing over them.
Even outside of the obvious English-French and settler-Aboriginal divides, perhaps there was a hesitancy within white English Canada towards an idea of a unified nationalism. Afterall, a huge chunk of that population would be descendants of Irish and Scottish immigrants who didn't do so well out of Old World attempts to form a unified British identity.
I don't see official Multiculturalism as reactionary at all, but as a great move forward in our collective conception of Canada. A conception that allowed us to see ourselves for what we were and are: a diverse group that lives together in peace and prosperity for the most part. What is reactionary, in my mind, is this belief some people have that what is Multicultural is foreign. It is not. There is a Chinese culture within Canada, and it is part of Canada. A traditional Ukrainian dance is as Canadian as ballet class. Canada has many faces, no one more valid than the next as they all inform our existence. They all affect us in some way and allow us to locate ourselves within the country and the greater world.
Does that mean we shouldn't teach Canadian history? Of course not, because to understand our society as it exists today, we must know where it came from. But one of the great things about Canada is that there is no real accepted definition of Canadian - we get to decide that for ourselves.
To put this post somewhat on topic, I'll echo what many are saying here. Dundas Square is it's name and there's no point in changing it now. Why would one want to? Dundas St. is one of the most fascinating and historically influential streets in the province.