OK, I realize this post is pretty old, but something else came up. Anyway, here goes:

So I was looking at modifying the PageCommentInterface.php, but then I saw in the code it looks like it is already setting Name and Comment as required fields with new RequiredFields:

$form = new PageCommentInterface_Form($this, "PostCommentForm", $fields, new FieldSet(
         new FormAction("postcomment", _t('PageCommentInterface.POST', 'Post'))), new RequiredFields('Name', 'Comment'));

That would be just fine with me, the problem is that I am able to submit a completely blank comment, no name, no comment. What could be the problem here? I have added an e-mail field to page comments using the tutorial from ssbits:

http://www.ssbits.com/tutorials/2010/adding-an-email-field-to-the-page-comment-form/

Could that have something to do with it? Maybe I need to add validation a different way?

Thanks for any help....