Unsubscribes cost you list growth and revenue. The way the current CF unsubscription page looks like, costs you subscribers. The reason: It only allows you to unsubscribe from a campaign or from all emails. The problem is the end user does not care about "Unsubscribe from Campaign" text, they are interested in what information they'll receive.
If they however see the different campaign names/topics they can subscribe/unsubscribe using checkboxes. Another option is to make choose intervals like weekly or monthly mails etc.
It would also be highly recommended to be able to BRAND/customize the unsub page with your company logo & colors.
Another good feature would be to have an exit survey to find out what went wrong.