It's possible that a lot of Mac users are simply not objecting to something they should. I have been using aluminum Apple laptops since they had a PowerPC G4 a

It's possible that a lot of Mac users are simply not objecting to something they should. I have been using aluminum Apple laptops since they had a PowerPC G4 and were called PowerBooks, and there have been some models with known heat issues. It doesn't surprise me to hear this about the new 12", I think what they're going for is doable, but perhaps ambitious at this stage. There was a 12" G4 which wasn't fanless, but still crammed too much into too small a package. I have a Unibody 15" MBP from 20011 or so that has absolutely no heat problems, have used several generations of 11" and 13" Air and both 13" and 15" Retina MBP and I don't have any substantial heat problems. One thing a lot of people don't understand is the thermal design expects to be on a flat surface so that there is some air under the machine, in the small gap created by the rubber feet. If you use any of these machines on a bed, a couch, on top of a pillow, or on your lap, they'll get hotter. I keep a piece of cardboard handy for when I want to use my machine in bed.