> Honestly, I'm tempted to make a fork of Cargo for Java, it's nearly perfect. But this goes against my opinion that build tools should be in the same language as the code they build.

The problem with that is that it doesn't work with slow / compiled languages. That's the worse thing about Maven (tied with the insane unnecessary complexity of the plugin architecture). The dev cycle for trying out a new plugin is atrocious. Compare that to editing a local copy of a Python, Ruby, or Groovy script.