How would one implement a re-assignment of a taskInstance? What if the current actor already "started" the task but wants to delegate it?
In a web environment, simply setting the actorId to another actor could lead to concurrency problems.
What about escalation after deadline/delegation? Any ideas?
Concurrency isn't an issue at all. In a web application you would simply verify that the current user still owns the task immediately before your code makes the reassignment--if they don't, you return a message to the web UI that someone else beat them to it.