Arters, very sage comment! As one would only expect from one of your years and experience in the AAR game.
One thing which might be considered, perhaps, is a podded centreline hose? We're seeing up to 1250 kg/min from the 907 pod, so rather than the more massive centreline hoses of the past, such as the Mk17 HDU, perhaps a pod mounted slightly off-centre (to avoid the need for additional Vmu testing etc) might suffice for the UK requirement.
Incidentally, many years ago we did suggest to the (retired) BJP that a boom would be a good idea - if only to guarantee a 3rd flight deck occupant! Because, at the time, the RAF was looking at only having 2 pilots to fly the 'Future Tanker'....
If the FSTA ever becomes reality, some form of centreline hose on 'a number' of aircraft is clearly essential. But TriStar experience would indicate that the ability to operate in the receiver role is not essential.