This is related both to scope and to design. An ontology is elegant if it has the fewest possible concepts to cover the required scope with minimal redundancy and complexity. Whereas completeness is about making sure enough is in the ontology, elegance is about making sure that the ontology is not done until there is nothing else you can take out. Once an ontology gets big enough, it is hard to remember exactly what is already there, so duplication and redundancy can arise. It can also arise in more subtle ways – you can end up with three different ways of modeling essentially the same thing if it was approached independently from three different perspectives. This is especially true if there are different authors, but it can also happen with a single author if the three different perspectives are approached and modeled at different times.