Something you're forgetting.  Any candidate has to have over 50% of the votes.  If 51% or more don't rank Kevin O'Leary he can't win, front runner or not.  BTW, don't rank him.  Further, with the ballots weighted by riding, O'Leary has to poll support across the country.  What past conventions show is that the candidate who is least UN-acceptable has a very good chance of winning.