New stage rendering core in Flash 10
* Live video playing in author time (meaning you don’t have to compile your movie to see how your video will be displayed)
* New timeline, similar to After Effects (or Director as some people have pointed this out)
* No more keyframes
* Transfer objects between Tweens.
* Bones
* Runtime Inverse Kinematics
* And more….

Disclaimer: Not all features listed in demos actually make it to the final release