The clamshell doors (i.e. the "tailgate" - tailgates are for trucks and American sporting events, BTW) might be problematic from a structural standpoint, plus are kind of redundant as they don't allow for any additional access to the cargo floor not already provided into the design itself. I also don't know if it's worth the expense of having A-2-A refueling capability, they're already capable of trans-Atlantic on a full load.