Last I checked, a non-weapon carrying cargo hauler is a really tough stretch to make into an "unnecessary weapon against cost overruns". The C-17 is one of the more successful programs the Air Force has.
Brian, perhaps you or someone else who has been in the military can answer this, but wasn't there a gap with the C-141 and the C-5 in their ability to land on non-paved airstrips? My understanding is that the C-17 can land in almost any field. I know the Soviets put a premium on having their cargo planes be able to land as close to forward operating areas as possible, rather than at an air facility.
C-5 was for heavy-lift capability and that's about it. Some fascinating facts about it, but I won't bore everyone. The C-141 was the medium-lift arm of the Air Mobility Command for a long time. It was a workhorse (dad flew them for 15 years) but solely for larger airfields. The C-130 was an all-purpose, small-lift capability (relatively speaking). All three planes debuted in the 60's, iirc. In the late 80's-early 90's, the AF needed a replacement for the -141's, and wanted to add the dirt-field and shorter-landing and takeoff capability of the C-130's to a heavier-lift platform. The C-17 is pretty much the workhorse of the mobility fleet.
At least you get a seat. Try flying from DC to Colorado Springs in the netting of a C-130. Luckily it's cold and noisy, though, so you can sleep.
McCain tried to get Boeing to build their 787 manufacturing plant in Arizona... when they didn't he has been trying to screw them ever since all in the name of 'joe public'. When the tanker contract is finalized it will cost 'joe public' FAR more than the original deal was for back years ago (for Boeing that McCain overturned)... and most likely will be paid to Airbus which is mostly run by Euro governments. Yep... just looking out for us that McCain is.