I would blame the result on the municipal mergers. Coderre is a suburbanite who probably would not have won if it weren't for the outer boroughs.
What seems clear to me is that Projet is probably never going to win the mayoralty. They seemed to be at their peak level of support. In order to actually have a chance of winning, they will have to put some water in their wine, or some of the former cities will have to demerge. Just imagine if the entire West Island was still part of the city! Coderre would have received his majority for sure!
Having said that, I think Joly could potentially win next election if people are sick of Union Montreal 2.0
Just look at this election map:
http://www.lapresse.ca/multimedias/e...cle_ECRAN1POS1