Thinness comes at a price. In more than one way.
That's the problem I have. They want thinner, thinner, thinner, but they're thinning it faster than actual components are shrinking in size.
Well the previous rMBP was thinner than whatever it was an upgrade to - but they managed to keep it 99.5khw battery (aka the maximum allowed on flights).
For me, battery life on these machines was such a big deal - to make a 25% hit for what amounted to a couple of mm thinner designs (which no one even wanted or cared for), holy ****. I used to laugh at the "Apple lost it's way train", but I may have to join them.