"And if there was a second round runoff, like there is in many countries, I suspect 90 percent of NDP voters would have chosen Trudeau. Not Harper."

By the time Trudeau has had his way with Canada in 2019, 90% of the Liberals won't vote for him.  
As for 2015, the Central Canada media elites dutifully beat the drum for Trudeau, falsely reported that the NDP might win, and thereby either discouraged or frightened moderates who otherwise would have voted Conservative. So, let Justin have his fancy multiple choice ballot; by October 2019 he'll be in Cuba teaching agitprop theatre.