I don't see how we can show this without sample identity data that provides a manager / subordinate relationship. So I agree with Tom that it should be deferred.
There's also the question of whether a regular user should be allowed to see other users' tasks. If not, then even having the Actor ID column be visible and searchable is unnecessary for these users, and the column should not be visible.
i would leave fine grained authorization out of the current 3.2 release and postpone it to one of the later releases.
this requires special care as that might make it much harder to rip out the default jbpm identity component. great care has to be taken with the defaults so that the authorization is natural, but not fine grained if you replace or remove your identity component.