If you look at the latest census data, you would know that much of the recent population growth in Saskatchewan and Manitoba has occurred because they have taken a more focused and proactive stance on attracting immigrants. I believe the Maritime provinces have recently started to follow a similar approach, and this should be encouraged across all provinces.

The reason immigrants tend to congregate in Toronto, Montreal and Vancouver is because few immigrants can name another Canadian city, which is to be expected, as when most look at other immigrant recipient countries, like Brazil, few are able to list of any of its cities other than Rio or Sao Paolo?

Lastly, you're also ignoring the fact that, once established, the second generation of immigrant families tend to fan out across the country in search of job opportunities.