I agree that I dont see U being interested, or in their right mind in they are, a significant amount of UALs Asia operation. Not only is it an expensive, complicated, and highly competitive market, it doesnt mesh with our fleet or current geographical location.
Internationally, I see US being a big player in the transatlatic market for STAR. TA flights will be the most greatly affected by war etc, but the demand will return as we are recieving new A332s. Keep in mind UAs IAD gateway would be gone as well as thier JFK-Europe, making PHL a more attractive gateway, especially for FF miles holders. The Carribbean is also very important, and an extension to Central America and even deep SouthAmerica (more A330s for that) would be logical extensions for the future. Asia, I think would be better served by the Star Alliance partners from U hubs and thier existing gateways.
But what U really needs to focus on is the domestic route system- granted , we are the biggest carrier in the most populated part of the country, but were missing the rest! I dont think U should go too crazy- a few additional flights to the hubs and minihubs from ORD, LAX, SFO. A Kennedy station should be opened to accomodate LAX/SFO-NYC, an important market were unable to serve from LGA, as well as LAX/SFO-BOS.
But Denver is what they need to try for. With one hub, youve got the midwest, west coast, and even the underserved mountain states covered. Its got great O&D traffic considering its location, a fantastic airport with room for growth, built in feed from Air Wisconsin and GLA (which would have more a/c available from ORD closure), no Southwest, and Frontier as the only signicant threat. The only international I see U doing from DEN would be LGW, HNL, and plenty of Mexico cities.