GIVEN that there is a doctor shortage in many areas, and
GIVEN that, for whatever reason, they are hesitant to let foreign-trained
physicians practise without further training/certification/something...

They should have a system whereby foreign-trained physicians work in
walk-in-type clinics in underserviced communities in exchange for
queue-jumping on the certification process. The public could know the
foreign-trained physicians' credentials so they could decide for themselves
whether to go to that clinic or do whatever they were doing before the
clinic arrived (waiting a long time, going to another town, whatever). I
can see why you perhaps might not want a doctor whose qualifications may not
be up to Canadian standards to, say, manage your regimen of psychiatric
medication or perform delicate surgery to repair your nervous system, but
that's no reason why they can't prescribe penicillin and give flu shots.