If someone is maybe having the same issue:
I added product reviews to the product view page.
After the upgrade the “submitted for moderation” message no longer appears after submitting reviews & they also do not show up in the db/backend.
In my case, the solution ended up being in /app/design/frontend/themename/default/template/review/form.phtml
<form action="<?php echo $this->getAction() ?>” method="post" id="review-form">
<?php echo $this->getBlockHtml('formkey'); ?>
Hope it helps someone else that might be having a similar issue..