I would like to be able to create network diagrams for development projects in Jira or Confluence to show predecessors and successors, show the critical path, and calculate slack. Ideally, this would use a set of issue story cards that can be dragged and dropped in the drawing space and allow links to be created between the issues. Once created, the links would show in "issue links" section of the issue.
Is there such a tool? It would make project planning sessions much easier; I currently use sticky notes on a wall as a visual aid.
Example: 
