What they need is a (relatively) cheap and simple aircraft they can afford to get into service in less than 5 years and not cost a lot.
Spending money on something they seem to think will be near r the front line will just stretch costs and development time so they'll finish up with a disaster. Those KC-135's won't go on forever - and there's always a chance some fatal fleet-wide flaw (as with the the RAF Valliant's way back) crops up and the whole fleet has to be grounded.
Jeez - just buy a lot of grounded 787's and fit probe and drogue tanks - nowhere near optimum but do-able