Hi folks, we released this feature in MailPoet 5.25.0, along with several other features: https://github.com/mailpoet/mailpoet/releases

There is now a survey when the user unsubscriber to ask for a reason. This is enabled by default, and can be disabled (or just textarea for "other" reason) in MailPoet > Settings > Basics.

Please give it a try and let us know if something doesn’t work as expected, or if there’s anything we should improve.

There're more improvements and features coming in the next few weeks.

Also, if MailPoet is working well for you, leaving a review on WordPress.org would help us a lot: https://wordpress.org/support/plugin/mailpoet/reviews/#new-post

Thank you.