I've posted a jira feature request for the requireAll tag lately, and Pete have encouraged me to show you my solution for the require attribute. Simply this tag let you forget about required attribute and simply annotate your model with @NotEmpty or @NotNull. It is also quite handy while doing templating with s:decorate.
I want to add this functionality to the <s:validateAll> tag. I don't want to introduce another tag. But aside from that, good solution.