In the assessment package we have questions that have some general data. But then we need to attach some question-type specific data and some display-type specific data which we now do with cr_rels in the cr since every information in assessment goes to the cr anyway.
When some data of a question is edited, a new revision is generated, but old mappings to that old revision should not see any change! Since the data in the mapped type-specific items can change, too, we really need a mapping from revision to revision.
Quite frankly, I don't see a problem in relaxing this thing a little bit...
