Any LD north-south service between Chicago and the West Coast would be a plus, IMO. It would open up dozens of new city pairs, and it would probably cut down on the number of transferring passengers in Chicago, LA and PDX.
What would be a good routing for such a service? I could see something maybe between Denver and Raton and connecting the Heartland Flyer to Kansas City somehow, maybe continuing to the Builder and Zephyr with either an Omaha/Sioux Falls/Fargo or Des Moines/St. Paul/Duluth routing, but I'm not sure how you connect, say, the mountain west state stops of the Empire Builder with the Sunset Limited.