It's true that most GWT apps use Widgets. They aren't going away; we have a lot of code built using them and migrating all that code isn't practical.

However, we would like to have more modern alternatives available for building a UI, as Ray has been talking about.

The projects I'm familar with use GWT-RPC more than RequestFactory, but otherwise your impression matches mine.

Compilation time is an issue because Super Dev Mode runs the compiler (in draft mode).