Is there a "time-limit"...?
In other words, this user is put in your user list when he's technically not a user yet, so is there a period in which if the account is not activated he's/they are cleaned out?
If not, what really is the purpose of this plugin? (an incentive to login, and retain clients if they want to eventually login?)
Could you maybe add a field or something in the User's, so we could only show them, and then download a user-list of them only, and/or be able to resend their validation emails, maybe with an email editor so we can add additional info etc.?
Oh, one other thing....
Could you add the ability to stop the email from showing the Title "WordPress" and the Email "firstname.lastname@example.org? Make it instead show the Website Title and also the email for the website? there is a plugin that does this, but it should be a function of your's.