I agree and would like to see this feature. We have a Discourse forum that was migrated from phpBB so lots of the old posts have messed up formatting for various reasons. I’ve been going through decade-old topics and editing them, but when I edit the last post in a topic, it is unfortunately bumped to the top of the “Latest” lists.
I have a simple feature request: allow moderators like me to type something like “#nobump” in the “edit reason” field to avoid the bump. This seems like a win-win: you don’t have to clutter up the user interface, but people like me who care can avoid bumping the topic without much trouble.
Another option could be an “Unbump” command in one of the admin menus so I can fix it after the fact. I suppose this would change whatever topic timestamp is used to sort the “Latest” list to be the creation date of the latest post.