Usually when politicians want more political clout, what they're really after is greater taxing authority. And since provinces and the federal government are not in the habit of sharing their taxation powers, that usually means new taxes. The division of powers in Canada's Constitution is clear. The federal government has sole jurisdiction in areas such as foreign policy, the military and currency. And the provinces have exclusive control over health care, education, welfare and a host of other direct services.
Cities have no official powers under the Constitution.
They operate under delegated authority from their respective provincial governments. Without Manitoba's City of Winnipeg Act, for example, Mayor Murray doesn't have a job. Canada's mayors have about as much chance of convincing Ottawa and the provinces to open the Constitution to give cities new powers as they do persuading Canadians to gut the monarchy. It ain't gonna happen. Cities are looking for new ways to tax people and they're likely seeking some kind of national consensus on how to do it.