XML view for filters containing user picker fields should return both userid and user full name

At the moment, the XML view of a filter containing user picker custom fields only shows the user ids. For instance:

...
<customfield id="customfield_10000" key="com.atlassian.jira.plugin.system.customfieldtypes:multiuserpicker">
    <customfieldname>Authors</customfieldname>
        <customfieldvalues>
            <customfieldvalue>userone</customfieldvalue>
            <customfieldvalue>usertwo</customfieldvalue>
        </customfieldvalues>
    </customfield>
...

In a way, this makes sense, because the user id is the unique identifier of a user. However, there are other applications that use this information and present it to the end customer. For instance, the confluence jiraissue macro uses the XML view to present the data in the Confluence page. That results in a macro that only shows the user id, which most of the times is not meaningful to the end user.

I would be good if the customfieldvalue could be improved to return userid, username, and user profile url, so the macro could present more meaningful view to the end user.

Of course, this should not break backwards compatibility of the XML view.