As
wrinkster22 the Air has been re-designed.
It is interesting, because although the 2010 model is better from a practical perspective (number of ports, access to ports, rigidity of hinge) from a purely aesthetic viewpoint I preferred the more tapered look of the old model with the drop down door.
In terms of improving the Air, Apple could probably shave off half a pound or more by moving to lighter weight materials like carbon fiber and magnesium alloy.
In addition the current 13" form factor could potentially hold a 14" display (as Lenovo demonstrate below), which would be an obviously useful:
Of course they could do a Sony and fit a non ULV quad core i7, 13.1" 1080p matte display, gigabit ethernet into a smaller, lighter, thinner package than the current Air. But obviously the price would increase. Really a Vaio Z (with Apple designed trackpad and keyboard) running OS X would be the ultimate mobile device. Apple and Sony should work together again, like they did for the Powerbook 100.
Overall though they have far more right than wrong with the Air from a price/performance/design perspective. There is no need to make radical changes at this point in time.