The Dojo Widget system has shown tremendous success, to the point that to many users "Dojo" is synonymous with the dojo widget system. In particular, it's been successful because of the widget template system and the parser, which allow developers to rapidly develop new widgets, and allow users to rapidly add widgets to their applications. It's also successful because of the many widgets in our library, including simple widgets like ComboButton to more complex widgets that even approach applications, like the Show (aka Powerpoint) widget.
There have been a some downsides to this development though:
In order to tame the beast that is widgets, the widgets have been split off into a project of their own. The main emphasis on the release will be speed, code footprint, and quality. In order to achieve this, only a subset of the existing widgets will be supported (more on this later). And also, only a subset of the existing infrastructure will be supported. Many seldom used features will be dropped.