This really is just raking up old previously discussed issues - search back for the Electra at Cologne thread for the full debate. Suffice to say, the Canadians allowed 2 crew operation first in arguably more challenging flying situations that Atlantic's. The FAA, UK CAA and Lockheed were all involved in the planning and implementation of Atlantic's 2 crew STC.
There is always an argument for the 3rd person on the flightdeck - however in this case I can say with experience that in my opinion, 2 crew worked well - anyone who hasnt experienced it just has to understand that. I experienced both 3 and 2 crew and so I believe I am qualified to comment on the matter.