"Whenever a Torontonian speaks of the city with a sense of importance they're deemed arrogant, think they live in the "centre of the universe", etc"
It's that dear old Canadian trait of 'eating our own'. Never mind the rest of Canada, even within the province of Ontario there is animosity and jealousy with regard to Toronto. To a certain extent this animosity is natural: There are lots of English who are resentful of London, and lots of French who hate those 'maudits' Parisians. Yet in a different context those very same people may be very proud of their capitals. It's all about the context. I don't think there is much to be done about the animosity of the rest of Canada to Toronto. It's all part of our massive regionalism and internal squabbling. Yet I find it hard to believe that somebody from Regina, for instance, would be disdainful of Toronto when talking to a foreigner abroad. National resentment of Toronto is probably about context too.
I do think that Toronto as a capital city should open itself up more to the province, even if only symbolically. On some level there should be a sense that the city is not just part of the province, but the heart of the province; that the city belongs to all in Ontario. Aside from Queen's Park, where does one really sense this at all? Where is there a sense of Toronto being the heart of a province, of the city being bigger than itself? Would a foreigner visiting Toronto get this at all? Maybe this is why Ontarians feel little affinity for a place that seemingly takes all the best, turning its back on the rest? It's all about PR and building image, and it's also another layer to our identity as a city that reaches beyond that of multiculturalism.
"I think one of the reasons London isn't ridiculued for calling itself the centre of the universe is that its claim to that title is fairly credible."
London is the centre of *its* own universe, and it is the perception that is more important than the reality. Toronto is the centre of its universe too, but we don't recognize it as so, blind to the intricacies of our own identity, always looking for our validation elsewhere.