I should add that i would not recommend writing new applications with blobs in the OpenACS content repository. In most quality dimensions the storage type "file" is better suited. The mentioned changes help admins to make old data again available to users, and to convert data.
I wonder if we should keep the lob interface for the content repository, or to write a conversion script to turn lob-entries into file-entries and drop the interface afterwards. However, i am not sure about the state/necessity of lobs in oracle.