As Hannibal would say: "I love it when a plan comes together". With jBPM being a platform for process languages, we never really fitted into the general accepted approach to Model Driven Architecture (MDA). While we do share many of the same goals like creating a better communication between business people and developers. We always believed that generating code from models was not the challenge. Instead,we always saw integrating the different languages in IDE tooling plugins as the real challenge. Now it seems that strategy is starting to pay off.
Ferran Rodenas gives a very good description of Visual studio and Domain Specific Language (DSL) tools. He's one of the few that can mix and match Microsoft with Java and other technologies. What's nice to see is that he opted for a modified version of our graphical jPDL eclipse designer in favor of a "solution based on DSL tools".
I think this really hits a potential problem with the current generation of Language Workbenches. They focus on building tools on top of a grammar. But more important and more difficult is the integration between all the different Domain Specific Languages (DSL) and general purpose programming languages. For example, think of a jPDL workflow process that refers to your class as a command. Then it would be really helpful if the class renaming refactoring propagated to the process. I'm not sure for all of them, but languages workbenches seem to be focussed more on building new languages and less on integrating the editors that result from that work.
For now, that is why we anticipate that the choice of the actually IDE technology platform (like eclipse) will be much more relevant then the choice of a language workbench. And that's why we keep on focussing to make the jBPM designer reusable and tweakable for all these kind of use cases.