Flash 6 support third party add-on's
Rather than trying to lobby for one or two new or improved features. Flash 6 should support thrid party extensions. Imagine Swift3d or Swish within Flash. What Xtras are to Director. Some want 3D support, others better HTML, XML intergration, a FlashTyper engine and so on.
If Flash 6 allows for third party Xtras as Director does. All request could easily be a reality. Macromedia could concentrate on a solid, bug-free application along with updating/enhancing existing tools, while other developers concentrate on creating additional add-on's that would extend Flash 6 tools.
This way user's can purchase only the tools(Xtras) they needed the most. This by far would be the biggest improvement.