The url and param tags are very flexibile, but the most common case of a single parameter link.
<s:url id="url" action="HelloWorld" includeContext="false">
<s:param name="request_locale">en</s:param>
</s:url>
<s:a href="%{url}">English</s:a>
is verbose (to the point of being silly).
It is worthwhile to have a streamlined link tag, a al Struts 1, to cover the single-parameter case.
<s:link action="HelloWorld" param="request_locale" paramValue="en">English</s:link>
In the interest of brevity, I would suggest that includeContext default to "false" for the single-parameter case.
Or, with a message resource key, from
<a href="<s:url action="Login_input"/>">%{getText('"sign_on"')}</a>
to
<s:link action="login_input" key="sign_on" />
New Feature
Open
Major
Streamlined link tag for single-parameter links
