My current Mac laptop (12" iBook G4) is deteriorating rapidly so, I'll probably buy an 11" MBA no matter what upgrades it has. That said, my biggest need is for it not to heat up enough to make the fan audible, even when used on my lap (graphics-intensive games can be an exception though, since I don't play games often anyway). Would really be great if it can even be used on a bed without heating up.
Unexpected features that I'd appreciate are:
Matte screen.
Audio input port.
The built-in mic being moved up to where the camera is.
SDHX slot. To fit it, I'd remove one of the USB ports, which should be redundant after T-Bolt's implamentaion.
4GB ram standard, with option for more.
Higher capacity storage SSD.
I could possibly enjoy a MBA with the same footprint as my 12" iBook G4, resulting in the 11" MBA having the same width s the current one but with the same depth (and subsequent screen height) as the 13" MBA. It's hard for me to decide on this though, as I've not used the current 11" for more than a few minutes so far.
I couldn't care less about backlit keyboard. The screen already illuminates the keyboard enough for me, even when I have the screen brightness turned all the way down to minimum, in the dark.