Although Google is investing a lot in it’s developer support, GWT was never a true open source project. Even now, the direction of the project is not communicated to it’s community. Google can decide not to support the project anymore and do something else, but not communicating with people who have adopted their technology is a wrong thing to do. Personally, I don’t trust Google open source technologies anymore and prefer now to work with pure open source projects.
We have collectively learned since, that it is much easier to get a grip of the modern web techniques, best practices and tools, rather than overcoming those with the GWT abstraction layer. The best practices of the GWT framework are good, however, those could be easily replicated in other technologies as well.
GWT promise was – “Productivity for developers, performance for users”. I have found that pure HTML5 and jQuery when needed are way more productive and better performing.