I wouldn't hold my breath for a new MBA. They have the Macbook now which is even thinner, and might get the market from the Air. Of course you're missing out on the USB-ports, Thunderbolt etc, but not everybody needs that.
My opinion; I'd go for the MBP Retina if it existed when I bought my MBA 2011. The Retina screen is excellent, and the HDMI port, 2x thunderbolt etc is excellent for connectivity (LAN + Monitor + External Harddrive etc)