Oh goodie a topic on geography I love this shit, I'm going to lay it down for all of you.
1) Canada has no black people b/c by American standards, SEATTLE has no black people and Seattle has HELLA black people compared to BC.
2) Black people aren't related to how good the rap music from the region is (Red Head Steve, Tha Loco, D-Sane and company have changed my views forever on that).
3) Black people ARE related to whether a city will blow nationally (that's why Seattle won't ever).
4) Vancouver acts are a part of the CANADIAN market, Vancouver is the L.A. of Canada so of course it's going to make a bigger impact on the Canadian scene than Seattle-Portland is in the American scene. And if you're gonna say that the two scenes are not independent of each other and that no Seattle-Portland act has made as much $ as the Swollen Members (which I would agree with, I'm going to a concert of theirs tonight at my school), the Swollen Members still enjoy that benefit of being from more of a comparative metropolis than the Seattle people do. I'd understand completely if some Seattle folks would want to move up to Vancouver (as Deep Thought & Touche did), they might have a greater chance at success.
5) Seattle is larger than Vancouver (200 statistics found 2.3 million in SEA not including Pierce County compared to 1.8 million in VAN including places such as Burnaby. Richmond & Surrey). Seattle is larger, that's not debatable (read "Regional Geography of the United States & Canada" by Tom L. McKnight).
As for whether it's a part of the Northwest, I say definitely, include them as long as their people don't tell fuckin lies like it is bigger than Seattle or that they have hella black people (LOL).