Excellent

I recommended adding this:
if(isset($_REQUEST[$param])){

to your code to make it make code safe.

foreach($params as $param)
    {
      if(isset($_REQUEST[$param])){
        if(!$return and ($rawtext = $_REQUEST[$param]))
        {
            if(($atts['dateformat'] != '') && strtotime($rawtext))
            {
                $return = date($atts['dateformat'], strtotime($rawtext));
            } else {
                $return = esc_html($rawtext);
            }
        }
      }
    }