We are constrained by the constitutional requirements. In fact, there was a referendum back in the 1960s on allowing for a higher level of representation in rural areas, thinly populated areas, than in urban ones. But that was politically motivated because, for the reason I mentioned before, the parties who do best in the rural areas know they would then be over-represented in the rural areas but still get their fair share in the urban areas, whereas the parties strongest in the urban areas would probably lose out in the rural areas.
I must say, from a European perspective, it seems to us that your ridings in Canada are already so huge that if you can cope with them as they are you could probably cope with them three or five times bigger.