Ipstenu, why I have to ask to a newsletter plugin to manage the standard user managing of wordpress?
If WP include a way to self register to comment, post articles, make pages, depending on the role, it must include a way to unregister as simple as I can do the registration process.
Try to think to a project with 200+ registered users, it's hard to manage their wish to go out from the project. Don't you?
I love WP, but this a must-have to professional user managing. :)
I can also write down some PHP code to do from the custom page, but it's not so usable to send users to one page to manage their personal info, and send them to another page to unregister from the site.
And WP is loved for its great usability and simplicity, above all.