Besides form-based dialogues there is more and more the demand for editing models in a graphical way. However, the development of such an editor is also very expensive.

Eclipse has several solutions for this topic, which show the progress of the overall toolchains.

SAP has soundly invested in the new Graphiti:
http://www.eclipse.org/graphiti/

plus there is also a chic DSL to create the models:
http://code.google.com/a/eclipselabs.org/p/spray/

what you can do with this basic stuff shows the impressive Camunda Modeler:
It is a BPMN-Modeler, which can also visualize the running workflow.
For more Information see BPMN-Workflow Engine

(containing task form editors also):

I am personally convinced that the future lies rather in JavaFX, not least because of its large community. I have never come across such a fantastic framework. There is something for every purpose and with the shape models you can very easily create a graphical editor with minimal effort.

see JavaFX-Post

A new JavaFX library for building diagrams is now available:
http://jankoehnlein.github.io/FXDiagram/