Another consideration which I have not seen mentioned is that (according to my sources, which are flawless and inviolable), while the original RFP specified an airframe sized such that existing ramps at USAF facilities could accommodate the tankers without modification, the Airbus proposed airframes are larger enough that, at many facilities, the aircraft would require relocation and pushback by tugs, while the Boeing entrant (and the 135s they are intended to replace) are able to taxi to and from the designated locations without external assistance. This is a significant mission capability issue.
I am further led to believe that, to the extent the Airbus entrant was “superior,” the superiority largely results from Airbus tendering a proposed airframe which exceeds specific design parameters as set forth in the original RFP - and that Boeing, had they believed a non-compliant proposal would be considered, could have exceeded the 767-based proposal’s capabilities, too.
Bottom line, I think, is that it is not and has never been a level playing field on this one.
As for the questions about the vertical stab’s strength, I am not convinced that this is an issue - will leave it to the engineers who know.