USE CASE: We use a custom property to identity when a contact is known to be a dead lead. However, many of these contacts have pending tasks associated which are no longer applicable once a contact is dead.
PROPOSED FUNCTIONALITY: Add a feature to workflows which would allow changing the status of a task or deleting it. Basically this would be just the opposite of creating a task from a workflow ... but perhaps a bit more complex to implement . Currently workflows auto create many tasks which now no long are applicable and must be manually deleted.