Add functionality to import/export unsubscribes from other mail services with a webhook or with zapier.

Offer an option or new campaign to allow abandoning users to sign-up to be automatically notified if the price of a product they viewed/added to cart has decreased.

Whenever a product is out of stock, having an email form field in place of the "add to cart" button that customers can enter their email address in to receive emails when the product is back in stock. There are other apps that do this, obviously, but I personally love cartstack with all of my heart, so I would prefer if they did it. I think one of cartstack's greatest strengths is the reporting dashboard, and I love having all of the analytics in one spot.

A/B tests should allow users to use the email builder (instead of uploading HTML) when setting up an A/B test. Users should also be able to copy over the existing template and be able to make edits to the A/B test.

Expand the functionality of the Exit Intent Popup so customers can select or copy the coupon code to be used at checkout.

Ability to add conditions (basic markup) in email templates to display different content based on different scenarios. For example, display coupon code if the user's abandoned cart is greater than $100; or if the user has a specific product SKU in their cart then display a free shipping message, etc.

A report to show which products are abandoned most often

Ability to send a targeted email blast to visitors that abandoned a specific product during specific time period. For example, if you changed the price of a product you might want to email everyone that has recently abandoned that product about the price reduction.

Display the direct link to the session replay in the dashboard so users can copy/paste to send to colleagues or platforms/engines.

If a user abandons the site and later returns (either by themself or through a recovery campaign), automatically re-populate the form fields that they entered data into during their last visit. This will save time for user (and reduce friction leading to abandonment).