Since I live in San Antonio, I see the C-17 all the time. I agree that the C-17 is misused for standard cargo, however, for military aircraft today, the watch word is "Multi-Mission Flexibility". The down side of Multi-Mission Flexibility is that it begins to look like the development of the Bradley Fighting Vehicle. If you have ever seen the HBO movie, "The Pentagon Wars" you will understand the reference. If not, I recommend you rent it and see what I'm talking about.
Back to the tanker problem. One of the issues that strikes me about the document you posted is floors and doors requirement to have the A330 be a Multi-Mission aircraft. IMO, the mission profile of a tanker makes Multi-Mission Flexibility more challenging and more expensive. If each of these aircraft is provided with a set of optional floors for cargo/passenger/medevac ops, it increases the operating costs because this optional material must follow the aircraft around to every TDY op area in the event that the mission profile needs to be altered in midstream. It happens (see the USS Pueblo incident for additional info).
In some cases, Multi-Mission compatibility works out such as carrier-borne Navy fighter-bombers, and attack aircraft that can also be used as tankers. The venerable P-3 has become a Multi-Mission aircraft moving beyond its intended role of ASW and assuming many of the electronic jamming, elint and ECM functions previously provided by the EA-6B. The more we delve into the specifics of this tanker deal, the less it appears that the AF has a clue what it is doing and the more it begins to appear (to me, at any rate) to be another Bradley Fighting Vehicle (see the video and you'll understand the reference).
“If each of these aircraft is provided with a set of optional floors for cargo/passenger/medevac ops, it increases the operating costs because this optional material must follow the aircraft around to every TDY op area in the event that the mission profile needs to be altered in midstream.”
I don’t think you have to buy everything for every plane.
Medevac units may be stored at bases like Ramstein with a big hospital nearby. I doubt you have to buy new ones if the old ones were fixed on 463L pallets. You can only transport patients in a stable condition. Therefore you got enough time to send a well equipped plane.
For passengers or soldiers you need seats. At each base some rows and for bigger events your general should know in advance.
With cargo you won’t have any problem except you got a KC-767A where the lower deck is full of fuel bladders. Both tankers are freighters with a cargo system for handling 463L pallets.
Mission flexibility for KCs is in my eyes not to change the mission in-flight.
KC-45: http://www.videocentre.eads.net/cutv/cms/_vm1500//_vv_1207655836006/fa_playlist/_skin_eadstv/1870/play?show=now&startClip=0&playSpecial=1936
(1:00)
or http://www.northropgrumman.com/kc45/operations/boomer.html
KC-767A: http://www.leeham.net/filelib/BoeingAFABrief.pdf
(p. 17)
On page 18 Boeing shows that there is a big chance to increase the use of tankers for cargo use to release some C-5 or C-17.