Bill Venners is president of Artima Software, Inc. talks about the addition of new features in a language and the challenges of backwards compatibility.
He has the exact point of view I have regarding this issue, programming languages with lots of features still need a good tooling support like the one we have nowadays with the Java platform.

What Scala and every other alternate language for the JVM currently lacks, however, is anywhere near tool support that the Java programming language enjoys.

Here he points the importance of great IDEs with features we can't live without anymore like Refactorings, static code analysis, etc.

The Java language has great refactoring IDEs, static analyzers that look for bugs, code complexity, and code style problems.

And says he thinks tool support is much more valuable than language features.

Nevertheless, the tool support for the Java language is so much greater, I judge it more appropriate to leverage that than to chase fun and productivity by experimenting with a new language.

For this path of using a different language for the JVM to actually become practical, some other language besides Java will need to become mainstream enough to motivate the tool support.

That's precise my point of view when talking about the Java platform, which has enough features and expressiveness that along with all it's ecosystem gives the developer a huge advantage in terms of productivity.