My vote: Sir John A. MacDonald
Our country‘s founding PM, a Father of Confederation and the architect who joined a loose confederation of colonies/territories into a Dominion that is what we have today. Without his visionary leadership and skills of diplomacy none of what we have today would be possible.
However I do strongly suspect Trudeau will win, as this country has been thoughly indoctrinated by the CBC to revere him. Everytime, I ask someone why they think Trudeau is great they cite his: 1) style, 2) he browns off the Americans and 3) the FLQ Crisis (although most can‘t explain what that was all about).
Louis Riel? Even if you are a westerner you can‘t be serious. This man TWICE attempted to over thrown the government out west. The second time resulted in a little affair historians like to call the Northwest Rebellion (1885), where the Canadian Militia and the NWMP went out to Manitoba and Saskatchewan. They then had several bloody battles with Riel and his followers, until Riel was captured.
He was then put on trial, found guilty and hanged. During the trial it was generally accepted that he was insane, as he told people he was Christ. No amount of retroactive historical rewriting will excuse a man whose actions resulted in that much trouble and a campaign medal being struck to commemorate the affair.