Foreign MD credentials are only sparsely accepted in Canada, with the majority of foreign doctors accepted being specialists from Australia, New Zealand, Britain, the US, Singapore, Switzerland, Hong Kong, and South Africa, largely from the mid-1990s onward. That excludes a
lot of foreign doctors, and almost all GPs. There has been a concerted push within the Canadian medical community to build bilateral credential recognition mechanisms, even in the face of GP shortages, and the needle hasn't moved much on recognizing doctors outside a limited range of institutions. So, at least within the Canadian context, physician regulatory bodies have judged the additional training to be beneficial for patients.
(In case you're curious, I've linked the Royal College of Physicians and Surgeons of Canada credential recognition criteria below.)
http://www.royalcollege.ca/rcsite/c...gs/jurisdiction/accepted-jurisdictions-e