Recently, while building the GMCP plugin (https://github.com/AbrarSyed/GMCP) for Gradle, we have noticed that things are slowing down when doing things such as patching source. It would be nice to be able to use @CompileStatic. We have been trying to figure out why Gradle does not use Groovy 2.0 and we have come to a conclusion that it has just not been done. While also in particular, we thought it could do with the fact that it would require tweaks to the DSL.
See http://forums.gradle.org/gradle/topics/groovy_2 for an explanation.