In Adobe DTM, there was a robust system that allowed side-by-side comparison of any pair of revisions of a single rule. I am now deeply missing that functionality in Adobe Launch.
Currently, I am able to easily access a revision of a rule that's in an Upstream library (for example, while I'm developing updates to a rule, I can see the current 'live' version of the rule) - but I have no indication of what changes have been made. Furthermore, I can't find a way to review an older, non-published revision of a rule without creating a new library and specifically adding that old revision (which, in of itself, seems like an issue).
Being able to easily see changes in Events, Conditions, Exceptions, and Actions would be tremendously helpful in diagnosing issues - especially in projects with multiple team members. Ideally, it would be nice to get to a level of detail similar to the current DTM tool that even gives a full DIFF of a custom code block. That said, even just knowing if a condition has been Added, Updated, or Deleted between revisions would at least let me know where to look.