Thanks @danilvoe for the feedback!
We have an open JIRA ticket to add an (Edited) label next to the post if it has been edited at least once.
Wondering if someone on your team would be interested in contributing the improvement?
By the way, Holiday Hackfest started on Dec 8th, which is an excellent opportunity to win an exclusive Mattermost shirt by contributing to the open source project: https://about.mattermost.com/hackfest/