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).

Give users more control over Exit Intent Popups on the dashboard. Let them turn on/off, adjust designs and A/B test.

Please build direct integration with dedicated email marketing platforms like Convert Kit, Get Response, Active Campaign, Aweber, etc. Having to export the Cart Stack email subscribers is an archaic method and using Zapier (if even possible) is just another widget to manage. Direct integration with email service providers is a basic feature pretty much every other "marketing" platform offers.

Add web push notification campaigns for abandoning website visitors

Using SMS messages to retarget users who have entered their phone number and have not finished their order. This would send the user a link to go back to your site and also give them the ability to reply with a question about the product(s) in their cart.

Develop additional Cart-Item layouts and allow clients to choose from a variety of options. Users should also be allowed to add UTM parameters to the product links.

Give users the ability to copy emails built in the editor to their 2nd and 3rd email sends. Users should have the ability to continue to use the editor and not be forced to edit HTML.

Add a cookie pool that will only connect all sites in an account.

Have the ability for customers to add additional campaigns outside of cart and browse abandonment. It would allow us to customize campaigns for customers leaving specific pages outside of cart/product abandonment. This will also help multi-language sites help keep all campaigns under one roof without needing so much customization.

Be able to export the contacts list.