Specifically, given that ISOLDE has live crystallographic symmetry (where the sym copies are represented as ghosts), would there be any possibility of implementing the same approach for point group symmetry - where the user provides the asymmetric unit and point group symmetry, and ISOLDE refines with point group sym ghosts?

This would be convenient, especially for interoperability with SERVALCAT, which implements this approach to point group & helical symmetry (very handy for many cryoEM structures that are refined with symmetry applied!).