There is no reason to split the North America region into West and East. You are only harming the game community by dividing players along arbitrary lines.
Why is it that Russia (a much bigger country than the United States with cities just as spread out) is able to have one region for the entire country yet Amazon is incapable of doing the same for NA? Are the AWS servers so poor that the ping would render the game unplayable with a centralized server location for all NA players?
The main benefit here is that you get a thriving community that ensures player population is always active and going so that you can find people to run content with… be it dungeons, raids, or PvP.