[iLoveYou]

What is missing in ActionScript 2.0?
Considering the number of new features introduced with Flash MX 2004, and the improvements in runtime speed in the new Flash Player 7, there is little more that could possibly have been squeezed out of Flash's 18-month development cycle. That said, here are some of the features that would make ActionScript an even richer language:

Abstract classes (abstract)
Final classes (final)
A real private scope
Protected classes (protected)
Real constants (constant)
Overloading
Runtime type checking