Mattermost PM here, thank you for the feedback! We are exploring the ability for users to choose if they want to collapse threads.

We’re very excited about it and are currently testing prototypes with the Mattermost community and some customers, with development starting soon after.

We'd love for you to join the Folded Reply Threads channel (https://community.mattermost.com/core/channels/folded-reply-...) on our community server as we share progress updates and gather feedback.