The Visual Studio trigger "When a workitem is updated" should get as input the fields that have been changed, so decisions can be taken upon the changes.
Our real world examples:
- I would like to catch all Bugs that have been set to a high Severity (bugs that had a different Severity before) and post this on a Slack channel or email them to the product owner so that they catch attention.
- Inform the person that created a bug when the state changes to Done (but only then) using email and/or slack.
So, in those cases I would needed the fields that changed and be able to add a condition based on them.