I agree, I modified the rating it was very harsh.
I think it would be highly beneficial to any developers out there to group your subscription information in a more easily decipherable separate table. You handle all the information through your php code and use the wpev_posts and wpev_postmeta tables, which makes finding all the subscription data and then writing the queries a bit more complicated. This adds a lot of testing and work to anyone trying to use this to support an external application that requires authentication. At very least add some documentation describing your use of the database…