Well first of all, I'm definitly NOT an expert and maybe I should do a search first so I might look like I know what I'm talking about but since I'm lazy...
It was my impression the 767s are new-build. So new aircraft with the latest available tanker-mods but essentially an old airframe design, it's true.
If the bus can pump fuel faster then it has a major advantage as dmf pointed out.
And the flying boom/basket capability provides a service even the F111s can enjoy (for a few more years). Depending on the JSF configuration, it may then no longer be needed except during multi-national exercises and/or operations.
As for proven technology I was probably getting ahead of myself as you're quite right, there aren't any in service yet.
Regarding commonality, what I meant was having two Boeings as opposed to one of each (Boeing and Airbus) would lead to some small benefits in an airline sense. The NGs, like the 767s, are not very digitalised in terms of systems (as opposed to avionics) eg the pressurisation system, fault-finding (bleed-leaks, fire-detector loop failure, etc), and so on. But I admit that in the RAAF the types would probably be completely sequestered from each other.
Ok ok Airbus wins..................
