Today we rolled out a few features that make using the /review path way more productive. see: Allow marking posts as reviewed on /review and hide them.
I think it would be fitting to add a new bronze badge called "reviewer" for people who participate in the review process.
In particular I think it should go deeper than just expecting people to click the "review question" button. Perhaps require a minimum of 'N' actioned items (list of possible actions are in the drop down)
Any thoughts on badge description / criteria?