FWIW: The keycap lettering is more reflective on the new Airs than it was on the backlit previous generations of Air.
I too liked my previous Air with the backlit keyboard, and when I considered getting the new one, I was worried about the lack of backlighting and tried the same experiment of turning off the backlight and trying to read the keys by the display lighting. It didn't work out too well.🙁
However, I purchased the new Air anyway and was relieved to see that the key labels were very reflective and could be read by the light of the display when necessary. Normally, I touch-type and don't look at the keys, but occasionally when surfing the net I quickly type something with just 1 finger and need to see the keys to do that. It works fine for me.😎