The company I work for has a demonstration Adobe AIR application that we distribute to customers. We have not tested it under AIR 2.0 until today but after updating the frame-rate has degraded substantially from the 1.5.X releases. We tried recompiling with the latest SDKs but no luck in improving the poor performance. We are now dreading our customers upgrading to AIR 2.0. We will of course try digging deeper and solving the problem but I'd be happy to share the installer with anyone from the Adobe team if they would like to have a look at it since AIR 2.0 was meant to be out of the box faster.
I'm sorry you've run into this performance issue. We'd certainly like to help investigate. Is it possible to get your projects code or example code that would show the frame rate degradation? Please feel free to PM or email me at ccampbel at adobe.com.
This issue has been opened as bug #2643332
I have the same problem with my application - ironically dropping the frame of my application (from 60fps to 30 fps) has the effect that it runs faster under air 2.0!
I hope you guys at Adobe can fix this.