a 3rd NA data center maybe?

[Claviusnex]

It would certainly make more sense to have three datacenters located by region (East, Central and West).

Won't likely happen unless server populations equal out. As of now, they just look at the distribution and say they don't need another center, players just need to even out.

That won't help the bottleneck through the instance servers as they are common across the datacenter. Being able to spread the high population servers across datacenters should help the bottleneck since they would no longer be competing for the same resources.