Airbus A330, which is larger than the 767, could also carry soldiers and cargo seemed to be a selling point.
Uh, why would that be a selling point when the USAF already has more C-17 than it wants or needs? Not to mention, neither plane is competitive with 747s, 757s, 767s and DC-10s used by contract haulers.
If any are even needed, the only rational refuelers are half-life, service proven airliners. The last I heard, the KC-10A has for years been the most reliable airplane in the USAF.
New KC-10A maybe made sense at the time, because McDouglas needed to fill its production line to keep it going, so they gave the USAF a sweetheart price, or so they said.
GB