Many of those doing the planning for the -400 at ORD don't have the foggiest notion of what's happening. For One? The Hangar and Ramp area at ORD are about to become a NEW Runway!! so the facilities to maintain the -400 will be impaired severely and ORD might become not much more than a Very large terminal operation as the new facilities have not yet started going up on the south side of ORD. Much of the expertise AND MOST OF THE resources to maintain the -400 are on the west coast and aren't coming back east anytime soon.
I can't speak to the Pilot base as I don't know but there's a LOT of consternation at Willis because some would like to retire the -400 and some would like to keep it, as of NOW? The A350-1000 will be 4 years out with no real guarantee that it will meet the present mission OF the -400. And there are NO alternatives immediately to be had on the marketplace.. to be short? We're in a Pickle!! what are the Alternatives?? the 747-8i, the A380-800 or the 777-300ER/LR of which NONE can be had in the short term. So I guess we fly the 777's we already have?? or we mix the 777 and 747 missions.