Provide a tree-grouped, labelled object diff, rather than a JSON diff. This makes it easier for the user to determine what changes have been made, as ZIDs aren't particularly meaningful.
We will want to split out differences on the Z2Kxs and group them together, like Wikibase does.
Technically, we WikiLambda needs to implement a subclass of SlotDiffRenderer
Some examples from Wikidata of structure diffs, for inspiration: