Civilization has a soundtrack where there are four iterations of each theme representing times from ancient to modern. There is a simple single instrument melodies in the Ancient era turning into modern songs by the Modern era. Most of them are based on classical works.
How should these recordings be connected to works? Would each four quality as a different work, and how would the relate to each ofhers and to the original classic work?
More info:
The way you describe it, it would make sense to create a work for each theme, with the versions of different eras as separate works (linked with arrangement relationships to the main work). For themes based on existing works, I would also add a “based on” relationship between the main theme and the work it is based on. I think adding links between the original classic works and the arrangements would be a bit too much.
The “arrangement” relationship seems to be particularly discouraged on MB; from the classical style guide:
There must be at least two different recordings available. The recordings must be of different performances by two different (groups of) performers. You must be able to source that the both performances use the exact same arrangement. If in doubt, do not create a new work.
The relationship documentation is sparse, but it’s the only other place I’ve found with guidelines on its use, and it says essentially the same thing (and even more strongly when it comes to pop music). Given that, I’d recommend that they should all just be linked to a single work – without any “cover” or similar attribute – and maybe given an “arranger” artist on the recording. Definitely support the hierarchical structure @mfmeulenbelt recommends for “based on”, though, whichever model is implemented.