I am indifferent either way to focusing the game in "Canada" or elsewhere outside the continental USA; meaning if they do I don't care, if they don't I don't care.
However, the core of the Fallout universe's setting is retro-satirical Americana and setting the game elsewhere would lose a great part of what makes Fallout...Fallout. This said, I would enjoy being able to visit other locations outside the US in a game; either via airplane or transport, I think it would be exciting if the story incorporated having to visit a foreign locale.
A spin off, like the scrapped game focusing on the Resources War in Europe and the Middle East before the bombs fell, would be most likely be the place where the setting might be outside the US.