Groovy dependency prevents adoption
The requirement for Groovy 2.0 is onerous on consumers, especially since it's not groovy-all. There are many cases where this conflicts with other versions of Groovy, e.g. trying to use this effectively in a Gradle plugin. For a library appended with "-java" it probably shouldn't require any Groovy at all, but that's another issue. But if you're going to use it, I'd recommend using the lowest possible version of groovy-all, e.g. 1.8.8.
Regarding the "-java" in the name - it means that it can be used from Java, not developed in Java. Regarding using groovy-all - now, when Groovy build is modular, we don't need -all anymore, why would be use one? Regarding embedding in Gradle - Gradle 2.0 will use Groovy 2.
Bottom line - I'll check the downgrade to Groovy 1.8.8 :)
And it should be "provided" scope.