Several years ago I discussed the notion of an A330MRTT 'lite' with a senior Airbus Military (as it was then) mate. The idea being a pre-owned A330 with minimum essential modifications to equip it for the AAR role. Similar in concept to the level of modification needed to convert the A310 to the A310MRTT / CC-150T in the early '00s.
No need for the complexity of the full-fat A330MRTT or Voyager - just a 2 pod design with a 3rd seat for an ARO who would have the same level of 'Fuel Operator Station' as in the A310MRTT / CC-150T including a Mission Computer System which actually works! No centreline FRU or boom, purely to keep cost to a minimum. Although the lack of interoperability with F-16 operators was acknowledged.
Unfortunately the hierarchy wasn't interested and preferred to offer only the brand new A330MRTT at at an eye-watering price.
The USAF is unlikely to adopt the probe-and-drogue AAR system, so the only real option is to stick with the much-delayed KC-46A or go back to the superior Airbus KC-45A which was the original choice over 12 years ago...….