Transformations / visitors are loaded from user project's libraries to participate on groovy compilation. It seems that classes of those visitors are loaded for each parse operation anew, which makes the parser startup longer.
Attaching a report (placed Logger.info() in TransformationLoader.findClass()) - about 570 classes are loaded after each keystroke + parse.
Mitigation step 1: have the loaded classes cached based on set of library URLs used by the project (cache the parent classloader).
Mitigation step 2: consider to disable InjectTransform etc. from Micronaut ...