Amongst other things, AIR 2 will provide access to the "native process API". This means that AIR apps should (at last) be able to start other executable applications - hurrah! This was a feature that was curiously lacking from AIR 1.0 as I commented previously.
Flash Player 10.1 will have a global error handler. At last! As the developer of a Flash-based application I can tell you that one of the major sources of irritation is having those nasty Flash debug traces pop up when an uncaught exception occurs. Some exceptions may occur from deep inside the Flex or Flash libraries so having the ability to respond in a more civilized manor is something that will cause many Flash developers to heave a deep sigh of relief.
More info on Flash 10.1 on the Adobe Developer Connection site. More on AIR 2.0 on the Adobe AIR Team Blog. Download the betas from Adobe Labs.