It's not exactly been bleeding edge the past few years. Now with the 2.7 release and the 3.0 release (which is hopefully coming very soon) it's receiving a major revival.
One of the most important new features are javascript interopt, which enables you to write libraries in java and let other people use it like any other js library. In the other direction, you can easily use javascript (libraries) in java.
That means it's possible to just use modern stuff like polymer from within gwt without much of a hassle.
One of the most important new features are javascript interopt, which enables you to write libraries in java and let other people use it like any other js library. In the other direction, you can easily use javascript (libraries) in java. That means it's possible to just use modern stuff like polymer from within gwt without much of a hassle.