sbt, gradle, and leiningen each bring a better syntax to build scripts, viz their respective programming languages. They each pitch the ability to drop out of their declarative syntax when needed, but from the samples I've seen of gradle and leiningen use in open source projects this facility is rarely used. I guess it's because replacing procedural build code with declarative was the reason projects bought into Ant and Maven in the first place. In my opinion Gradle would do well to replace its Groovy DSL with its own lightweight one with a similar DSL and let developers use Java lambdas to do any procedural customization if it's ever required, just like they removed virtually every line of Groovy from their codebase for Gradle 2.0.
