It'd be the first build system for any JVM language that would be nice. I don't know what it is, but they all seem to come with various amounts of suckage (started with Java when GNU Make was the most advanced option, via ant, maven, gradle, buildr, sbt, ...). It must be the JVM. I worked with Scala for close to a decade now, and my conclusion is that its advantages (type stuff) are mostly theoretical, and its drawbacks (sbt, type stuff, the JVM, slow compiler, the mess of features) are mostly practical. I'm happy to have mostly moved on.