sprucemoose, the only reason they can't been snapped up as tankers is that other people have been quicker off the mark!
A310MRTT is the only 21st century tanker actually in service; A330MRTT will be a top jet for the Aussies and CSA A400M will also have a good AAR role.
I'm not a believer in PFIs - but I most certainly am a believer in both A310MRTT and A330MRTT as excellent strategic AT/AAR aircraft! Whether the full capability of the A330MRTT would routinely be used is something the customer would have to consider - does he want 110 tonne in one place or 55 tonne in one place and another 55 in another. Or 2 x 55 tonne tankers in cell offering 4 hoses in the formation in preference to 1 x 110 tonne tanker offering only 2....
One presumes that the customer will have "done his maths" when it comes to procurement preference, should there be such alternatives available to him.