I can only agree.
Had the MBA 13", upgraded to the rMBP 13". The rMBP is actually quite a bit heavier. It's thicker and I also much prefer the wedge-shape of the MBA. What I'm trying to say is that I miss my old 13" MBA. However, that old display was awful. It gave me eye-strain before I was even used to Retina Displays. The display was the one single reason I upgraded.
The rMBP has the best laptop screen I have ever used. It's absolutely amazing. So good in fact that I can put up with the extra weight, thickness and slight UI-lag.
However, a MacBook Air with Retina Display would have been the best laptop computer of all times! Why, oh why Apple...
And no, the rMBP is not really a viable replacement for the 13" MBA. At least not to me. It's a different product altogether.