It's the weak "I guess I support him" kind of people who need to be swayed - and I think to do so the other candidates need to condemn him in simple, harsh, constantly repeated language - i.e. he has horrible judgement, he is friends with criminals, he's been drunk (at least) on the job, abuses the office, he could've killed Torontonians by driving drunk, etc.
I tend to disagree. The people who make decisions on moral grounds - i.e. who don't want a crack addict mayor - have already left, because there has been tons of evidence about that for a long long time. Anyone who would be swayed by that has already left.
The people you have to work on now are those who say, "well, he's a bad person, but he's still the best mayor we've ever had, look at all he's done! What does it say about all those career politicians that the crack-addict is still a better mayor than they were, right?".
I believe that he has been an objectively bad mayor who has made things worse for Torontonians, and I think these people are provably wrong. But if they only get their news from TV, friends, or the first page or two of the newspaper, they'll never hear that. They'll keep thinking that Ford is a bad person who is nevertheless a good mayor, and they'll hold their nose and vote for him. The unscientific polls last night support this - people still believe that Ford, somehow, is the best economically, and as long as the papers focus on the bad behaviour, it'll never come out.
I voted for Smitherman on much the same basis, and I will probably vote for the Liberals in the next election for the same reasons. Different in scale, of course, but the same underlying principle.