The current behavior of the list version of /badges/{id}
is to return the users that have been awarded any of the badges in the list.
An alternative is to have the API to return the list of the users that have been awarded all badges in the list.
I can see how both could be useful. In fact, if I was to write an app to screen for potential SO users to solicit for biz opportunities, I'd like to be able to do both types of queries.
However, the usefulness of the current implementation is bit limited by the fact that determining which badge from the list particular used got, requires additional request.