Yup, I know I can get away with 4GB if I'm careful because that's what my current 2007 MBP has. But will I still be able to use the Air for work when it's that old? I suspect 4GB will be comically small in 2015.
The modern SSDs in the new Airs makes a colossal difference when swapping. I've never had any problems with only having 4GB RAM on my previous gen 11" MBA, and I'm regularly running a host of apps and doing active app development with Xcode.
Swapping at 2-400MB/s is far less painful than swapping at ~15MB/s.
