The aircraft will carry items which won't fit in a C-130 at speeds greater than those of a C-130 to places where a C-17 cannot go.
Once again, I am NOT knocking the A400. It does what it was designed to do. My questions is, what was it designed to do? Was the requirement just to carry stuff a bit bigger than a C-130, but not really big or heavy stuff, and carry it a little faster than a C-130? What kind of stuff do the European armies have that are just a little too big for C-130, but still small/light enough for an A400?
Edit: When spec'ing the C-17 cargo floor we found that any Army stuff that was "outsize" for the C-130/C-141 (they have the same cargo hold cross section), things got really big. The 10 ft wide cargo floor of those two aircraft is a natural sweet spot. Small increments in width resulted in smaller increments in capability. It was not until C-17's cargo floor got to 18 ft wide that it reached another sweet spot. Another sweet spot is at 19 ft, which is the width of the C-5 cargo floor. But that was for US Army and USMC equipment. Is European military equipment that much different than US equipment that there's a sweet spot at 13 ft?
As for going where the C-17 can't go, the C-17 goes to 90+% of the places a C-130 can go. So of the less then 10% of places that C-17 can't go (relative to C-130), how many can A400 go to? And what drives that? Field length does not seem to be the driver keeping the C-17 out because A400 and C-17 have essentially the same field length requirements. Is it CBR? Are there that many airfields 3000 ft or longer with a CBR less than 12?