For most developers the editor is the place where he is spending most of his working time, therefore we could try to make his life easier by providing web services related editor improvements.
These improvements can be made in following categories:

-context sensitive code completion/proposals
example: user types '@WebService(endpointInterface="|")', invokes code completion at '|' and completion will offer him list of applicable interfaces available in current project/workspace

-error checking
example: user has an empty class annotated with @WebService - this class compiles fine but is not valid web service due to missing web service operation hence the editor should show some kind of error and provide some hint/proposal so the user can easily fix it; hints could be ie Add ws operation, remove Web Service annotation

All these improvements should be based on rules defined in JSR-181 (eventually JSR-224). I don't think all of them should be implemented but having at least some of them can be pretty useful.

To start a discussion about what to eventually implement, here is a kind of a spec we could reuse: http://wiki.netbeans.org/SpecWsEditorUI and an umbrella issue[1] in NetBeans bugzilla covering few other related items which might not be in the spec itself

[1]: http://netbeans.org/bugzilla/show_bug.cgi?id=78758