I have a national identity, but I don't feel a need to impose it on anyone.
Also, I tend towards capitalism for the most part with some exceptions. If everyone started moving to Canada, wages would go down and costs would go up until Canada were not so attractive anymore. The same applies between cities by the way. For example, if you work at a home office and can work from anywhere in Canada, why would live in Toronto unless that's the only place where you can work?
The same would apply on a world scale. Anyone who could produce something abroad and then export it to Canada would probably prefer to stay home. So the flood would not be as bad as you think as long as we do not give them social assistance. I was talking about allowing people to work in Canada visa-free, not giving them permanent residency. That too could make moving to Canada somewhat unattractive.
The larger population would feed construction, increase population density, and so allow more efficiency through economies of scale. The market would adapt.
As for languages, how are those any different from any other qualification? we need other languages to better trade with the rest of the world anyway, no?