Evolution of Languages

After working a while with Groovy in a project I have the impression that it is the better Java.
Mainly because it introduces nice productivity features such as closures, runtime compilation, loose typing, operator overloading just to name a few.
These features are available in C# for instance as lambda expression, extensions methods or type inference. And runtime compilation and operator overloading are even part of the .NET-Platform since version 1.
But while the C# language evolves from version to version in a logical way, in the Java world a new language is created. It is called a scripting language. Why that? Every language that can be compiled at runtime can be used as a scripting language.
I think it would be better to add those productivity features to the next version of Java without further cluttering the Java platform. This would help developers and decision makers to choose the right technology.