Steve
En-Route
In a conversation with a friend who is an Air Force fellow, I was told that the Airbus/Northrop entrant was too large for many existing ramps, and that if they went with that design, they'd have to use tugs where now, and with the 767-based entrant, they do not.
In contrast, talking to some tanker pilots I know, the argument for the KC-45 was, in being larger, had enough additional capacity that fewer airframes would be needed to support the fleet reducing overall maintence demands, could stay on station longer servicing more aircraft, and travel farther to the rendezvous point.