Ottawa, Calgary, Quebec City, and Winnipeg could likely all have enough support teams. If MLS goes to 32 clubs, I would suggest there be at least 5 or maybe 6 Canadian ones to bring Canada into the fold more.
Winnipeg has NHL and CFL in a city of well under a million. Quebec City is that size, too. They get a team sometime after Bakersfield. Which is to say never. Canada is small. It has about a tenth of the population of the U.S. It has only three metro areas over 2 million, with three others between 1 and 1.5. There are over forty American cities larger than Calgary, Edmonton, or Ottawa. MLS Canada is built out. Toronto for Ontario, Montreal pour les Quebecois, Vancouver for the West.
Garber has stated on record that there aren't going to be any more Canadian teams. It's the Pareto Principle - the three MLS cities contain 30% of Canada's population. If you include each MLS city's provincal population as possible fans, that number rises to 75%. The Canadian Premier League is rumored to be starting in 2018 and may include a team in the Toronto area (no TV contract is possible without it), but probably not the other MLS markets. It will probably start out with 7 or 8 of the following cities: Victoria, Edmonton, Calgary, Regina, Winnipeg, Hamilton, Greater Toronto Area, Ottawa, Quebec City, Moncton, Halifax.
Calgary and Ottawa are likely the only options if MLS were to ever consider expanding there. It's 10 hours straight through from Calgary to Vancouver. Vancouver is not drawing a significant amount of fans from Alberta.
Calgary..quebec city snd winnipegway too small for mls and would not get the support to survive..OTTAWA could be a goid mls city