Not sure if you fly through there often or not ... But to me, it looks like SEA does not seem able to handle much more traffic, especially if Delta says they are going to "double" their traffic. If a lot that growth is heavies, which requires increased spacing for wake turbulence and they only take-off or land on the inside runway, that will further affect SEA's traffic flow. Sorry to use logic, as I know it may not help you bubbas sleep at night...