> Actually ORM does expose add/update/delete but via the JPA methods like persist / merge / remove.

Haha . I haven only used the JPA interfaces of Hibernate, yet.

About the hierarchical entities:

I don't really know what is needed to support that or what has to be changed, but in my opinion that would be a relevant feature (at least for my implementation).

I don't know all the things necessary for my implementation yet since I am not finished with designing. I think I can provide you at least with some details later this week.