I think traditionally, historically, for a lot of Canadians that is not regarded as an appropriate day for that kind of public political activity, so I wouldn't be favourably disposed to a Sunday date.
I think that since Sir John A's day, or Laurier's day anyway, the tradition has been Monday, or Tuesday if the Monday's a holiday. I think that's what Canadians are used to, and I don't see any reason to change that.
As to whether it would change turnout, it might actually diminish turnout. There are a lot of Canadians who just simply wouldn't vote on that particular day.