The japan servers also benefit with having all of their players relatively close. The architectural decision made by SE to have a single NA/EU datacenter is likely the source of much of their congestion issues. I can only imagine what SE's ISPs are trying to do to cope with this in Montreal.

Architecturally it would have made more sense to distribute the workload across multiple data centers. Have NA(east), NA(west), EU/UK, Oceania zone.
Put 25 servers in each NA datacenter, 50 in the EU centers(distribute across multiple DCs some in Britain, some on main continent) and 5 in the Oceania zone. That would quadruple the number of servers allocated to the current US/EU players base and still provide us with only half of the player to server ratio that the Japan player base currently enjoys.

Someone at SE might argue that would be expensive.
Your player base might argue that having millions of people return your product for a refund because it is unplayable is more expensive.