Dimi, I still don't get you, what you are saying is: changing class=todo to class=done is considerably easier then changing class="todo" to class="done"
Rule #1: whoever is willing to do the thankless job of maintaining pages on the web site gets to tell anyone else how they'd like the formatting to be.
Since this issue has directly affected me in the past I will point out a real argument for making this stuff compliant:
If I copy and paste the HTML into a WWN it would be nice if I didn't have to do a ton of markup to make it well-formed. In fact, I almost never reference anything on WineHQ for that very reason. For example, in issue #143 I went through the markup for the original to-do list and corrected it (which is interesting to look at now, btw).
Likewise, it's simple to copy things into the documentation. A good example of which is: http://www.winehq.com/site/status_options Parts of which may end up in the User Guide.
But that's just me, and I ain't the one maintaining it. So if Dimi doesn't want it then I guess the best thing to do would be to resubmit with those parts left out.
-brian