News to Mr MacDonald, but the Law Commission of Canada (now defunct, sadly) presented a thoroughly researched and extensive report on this subject in 2002. 

They recommended a mixed-member proportional system with regional open lists alongside our current single-member ridings. They also went to some length to explain the justifications for change (not to say that proponents haven't been giving specific reasons ever since). I'm not sure why you would claim proponents of electoral reform offer no detailed case for it. This is not only demonstrably false, but makes me wonder whether you are being deliberately disingenuous. Or perhaps your article is simply that poorly researched?

Read the Law Commission's report here: 
http://publications.gc.ca/collections/Collection/J31-61-2004E.pdf