There was some discussion about the graphene coating and IIRC seas also emphasized it's use for preventing, I think, Oxydization especially in certain climates. So I think there is truth to what gadios wrote.
However, the new Graphene Seas drivers were more than the coating - other aspects of the driver were re-designed, which is one reason the crossovers had to be re-designed/tweaked for their use.
All together, with the sight changes in the drivers and Jeff Joseph tweaking the crossovers, it makes sense the new Joseph Graphene speakers would have evolved their sound somewhat.
My local JA dealer finally got the graphene Perspectives in so I'll probably hear them this week or next week.