(sorry, too busy booking a bunch of trips ex-SEA to use capitals or proper grammar)
On a more serious note - upgrade lists for SEA-ATL/DTW/MSP are going to get even more difficult than they already were, especially for non-SEA-based elites.
I wonder if this works for both segments of direct flights (e.g. the current SEA-NRT-HKG "direct" marketed as a single flight number). If so, that would be the one time in history that's actually worked in our favor...