Yes, it may be worth considering adding the functionality which would let users create custom clusters of properties. E.g., a little while ago I was just adding similarly constructed links (using the External ID datatype) which are in fact URLs pointing to lists of publications in a library catalog (these URLs use author IDs as search parameter and this ID is what I add as a value while the remaining part of the URL is adding from the formatting URL property value). In this case it may be useful to have a separate property cluster entitled e.g. Publication Lists.

This would be a great feature as otherwise the item page may often look cluttered even though the properties can be (on the Wikibase-SortedProperties page) ordered in such a way that non-identifier properties are listed first and then followed by the identifiers (as @OlafJanssen and @Addshore have already mentioned in the comment above). I would certainly use this feature once it is available :-).