Found a partial workaround, based on the absence of checks on the background color specified in a report template. Since background color is now done with CSS, we can specify something like<br>
WHEN status='CLOSED' THEN '#909090; text-decoration: line-through'<br>
in the template, which gives us this HTML code<br>
&lt;tr style="background-color:#909090; text-decoration: line-through"&gt;<br>
and a correct style. Of course this gives us limited design opportunities, but it is still better than nothing.