Hey Eclipse, come join the Sun party
I was looking at JSR 198 again and noticed they had released a "Proposed Final Draft" last month. Some Eclipse member companies are on the expert group but as far as I've been able to tell, the proposal itself would be very difficult if not impossible to implement in Eclipse. It looks more targetted towards NetBeans and JDeveloper. One reason: the Eclipse Foundation itself isn't on the Expert Group. The Apache Foundation is, so why not Eclipse? Eclipse isn't on the Executive Committee either. In fact, Eclipse is not a member of the JCP at all.
I feel it would be hypocritical of me to suggest that Sun join the Eclipse Foundation without also suggesting that Eclipse independently join the JCP. JCP has its share of problems (such as Sun's special position and veto, and the lack of transparency in JSR development to non-EG members), but that's not a good reason not to join. Eclipse could follow the Apache model there.
In my opinion, JSR 198 shouldn't be approved until there is a reference implementation for all the major Java IDEs, including NetBeans, Eclipse, and Jetbrains IDEA. That's the only way to tell if it will work and be "helpful" both to the framework providers and their consumers, the plug-in providers.