I have long since been much less interested in performance in my laptops. In fact, if it weren't for the fact that my 13" MacBook Pro has mediocre battery life, is heavy, and doesn't have Retina, I'd continue to use it. Performance-wise, it's perfectly fine for everything I do.
So, yeah, I want something lighter, with longer battery life, and which has Retina. These new Core M CPUs are perfect for this. Ultra-low TDP, but twice the CPU performance (representing an upgrade for me), and 7X the GPU performance (meaning Retina is easy).
And ultra-low TDP means not only means no fan and longer battery life, but it means smaller volume and lesser weight, including from the smaller batteries necessary.
Think iPad, but with laptop-class performance and a keyboard. In fact, it almost makes you wonder if this rumoured new laptop will be a touchscreen device, although I don't think it will be.