I would love to set Solid Regions and Copper Areas to be Multi-Layer. That would make the object appear on every layer. That would ease a lot to make matching Copper Areas across different layers or it would make No-Solid Regions just a single object instead of 4 or 6 object in multilayer boards... It would also solve the accidental misalignment of these objects when placing them manually. In short it would be a big quality of life improvement :) OR even better: offer a checklist for these Objects where the user can toggle every layer on/off that should contain the object.