IU requirements for hard/soft delete
Our current DSpace-based repository uses the 'tombstone' concept, such that in general, items that are removed from the repository through the interface will keep a 'tombstone' marker page that displays a message indicating that the item has been removed. There is also an 'expunge completely' option, which removes the tombstone and all traces of the item from the interface, but doesn't actually remove the item from the repository. These two options represent the experience we'd like to keep.
So, to summarize, for IU's needs, there is no need for a permanent 'hard delete' ever for items that have been fully ingested into the repository, as long as the item can be hidden from the interface through some mechanism.