Many friends of mine were willing to develop Idea plugins some time ago, but all of them failed.. because "it is not stable..", "there is no documentation" or "the languguage API is not just usable..".. and they develop Eclipse plugins now. Some of them are eclipsers now.. unfortunately.. but not surprisingly. They have their reasons. They have the tools they need in Eclipse.
We need tools, but JB is not able to develop all of them.
Why is it possible to develop e.g. a sound editor with NetBeans? Because it's a free platform. And it will be just a sound editor without java support at all. And you can sell this editor. And it makes sense to do it.
Can you develop it as Idea plugin? Yes, but nobody will pay extra $500 for EJB support in sound editor.
To JB: Are there any plans to make a core of IDEA a free 'platform', like Eclipse or NetBeans? I mean the toolwindows, menus, actions, plugins container, configuration, plain-text editor etc? It should not necessary be open source, just free and documented. And we will pay for the rest.
'The platform' will not create cash but it will create volume. And it will be converted to cash in the long run. Even when L&F of a new app is familiar you feel "at home"..