I'm back to playing with this and have some more suggestions for future updates.
The show all user reviews link is on the showmembers script. I knew it was somewhere front and center.
The problem with the showmembers (Member Products link on the navbar) page is that it lists only the persons who have uploaded product pages. It does not appear to list anyone who has submitted reviews (comments), unless they have also uploaded at least one product.
It would be nice if there was a separate page (or modification to this page) to also show those who have submitted only reviews/comments, even if they have not uploaded a product themselves.
Here is an example if you want to show the same see all user reviews link that is on show members script on the showproduct page you can edit the showproduct template and under the line noted add the line in bold here
This also only shows the reviews of the person who uploaded that product. What I was getting at originally is that under each product on the show product page are the authors who submitted reviews for that product. It would be nice to have this function to see user reviews somewhere in this profile, perhaps under their avatar along with the total number of reviews/comments they have submitted. This way, when you see someone who writes great reviews, you can check out their other reviews more easily, even if they haven't uploaded a product page.
Similarly, in the "Top Posters" sidebar widget, it only credits those who have uploaded a product. It would be nice to have a "Top Reviewers" widget too, since you want to credit all those members who are adding content by reviewing the uploaded product as well.
So these may be suggestions for a future update. In the mean time, is there a clever way to show a list of the top reviewers, sorted by the number of reviews/comments they have submitted, again even if they have not uploaded any products themselves?