The US majors reprioritise their hubs after a merger like this. Some will win, some will lose, some might close. Delta used to hub at CVG, offering flights to LGW, as did Continental from CLE to LHR/LGW. Most of the traffic is connecting on elsewhere which meant it could be accomodated over the remaining hubs fairly easily. Delta out of MSP is not as big on long haul as NWA wa out of their home base.