The problem of fringe parties gaining parliamentary leverage is easily solved in a carefully crafted PR model.  Mr. Trudeau expresses a very narrow, limited view of what a PR model is.  PR is not necessarily one model.  There are many PR models available for consideration - it would be the job of parliamentarians and constitutional experts to analyse and recommend the best one.  The common reference to PR implementations in other countries is interesting, but I believe that Canada should design its own PR model rather than adopt another existing model and then try to shoehorn it into the Canadian culture.  Surely Canadians are smart enough to create a Made In Canada system of government.