Yes this would be incredibly helpful, I’ve just come here to raise the same request, and sad to see it isn’t popular.
For complex workflows in which simply referencing $json from the previous step isn’t enough, and you need to reference various previous nodes, it’s currently really difficult to see where those values are used across the workflow to update them.
The only option I can think of thus far bar looking through each node is downloading the JSON and searching for references, which is not a great user experience.
Potential duplicate of Button to see all nodes references