I think this would be a bigger deal if AIR was made available on Blackberry QNX, Windows 7 Phone and WebOS as well.

I'm not sure that most desktop AIR apps will translate nicely to the mobile experience at first, nor will you see a lot of nice ports of desktop AIR apps for some time.

Having AIR across all the major mobile OS's (except Apple's) would make it quite compelling as a mobile development platform, though.