Please add your own entries, and increment the vote count for features that interest you. IMPORTANT: Please try and consider your suggestions from an IntelliJ design and terminology viewpoint rather than trying to insert ideas that are concepts from other browsers that don't make sense in the IDEA world.
Code Formatting (as currently supported for Java code)
Auto insertion of packages and imports (as currently supported for Java code
Syntax Highlighting (including the ability to color Groovy specific constructs differently)
Live Templates support
Execution & Testing
Ability to run Groovy based tests in a similar fashion to standard JUnit tests, with matching green/red runner results view.
The ability to specify Groovy Run/Debug configurations for scripts and classes. (Scripts shows in the current editor should not require the developer to setup a run/debug config and should be executable via the standard shift-F10/F9 hotkeys.)
Full debugging support, including setting breakpoints, watch variables, view stack, view vars in scope, etc.
Support for transitioning from Java to Groovy and vice versa.
Ability to filter stack traces to show only Groovy classes.
Ability to debug scripts in addition to classes.
Find All References
Ability to specify Groovy specific code style
Cross compiler allowing to reference Groovy classes from Java and Java classes from Groovy