Normally the GWT team does not comment on future milestones, releases and does not provide an official roadmap (Issue 7013).
But this time, the team posted several comments on whether GWT is dead or not (mainly because of the fuss around Dart), and Ray Cromwell posted a comment providing some insight on what is coming on GWT 2.5:
The next release or two of GWT may include more core improvements than the last few point releases of GWT so far, consider:
1) Compiler optimizations that reduce code by size by 30% uncompressed, and 15% gzipped
2) SourceMap support and Source-Level Java debugging in Chrome (and hopefully Firefox)
3) A „super draft mode“ that can recompile many apps in under 10 seconds and most under 5
4) New „to the metal“ „modern browser“ HTML bindings
5) Testing framework that makes GUI testing delightful
6) Incremental compile support to speed up production compiles
So code will be getting smaller, faster, easier to debug (in some situations) and test, and compiles will go quicker. This reflects somewhat the shift in GWT team composition, but as people ramp up on other parts of the SDK (e.g. MVP stuff), I’m sure there will be improved responsiveness to fixing bugs in that area as well.
Add this to the list of issues already fixed and scheduled for 2.5, and we will have a really interesting release.