@Francesco,
Sure (and I was only speculating). Though, it's not clear to me, if those specs are just for the Air run-time? (Ie not for the compiler or any other executables included in the Air sdk).
I can believe that XP support might slip through the gap on the new compiler, if XP had to be supported in its own right. 32 bit systems in general would surprise me. As I say, I'm just speculating.