[wsia][wsrp-interfaces] Specific or general destroy mechanism(s)

The current draft spec has a generic release mechanism (releaseHandles()).
At times more specific mechanisms have been mentioned (deregisterConsumer()
& destroyEntities()).
Advantages/disadvantages I see for the generic mechanism are:

Advantages:
  - Single operation in the interface
  - Extensible ... can easily deal with new handle types as they are added
to the spec.
  -
Disadvantages:
  - Implies an inheritance relationship between handles. This isn't bad,
but isn't required for specific mechanisms.
  - Type checking moved to the application level (this depends on how we
specify the serialization of the handles).
  - Harder to explain as the operation is more abstract and therefore
dependent on what is concretely passed.
  -

Comments / thoughts / preferences?