I would kill to have the San Fran zone move to the London waterfront area. Less sets, more fog and pure scares, maybe even construct a sort of canopy walk through area would be neat.
But since it would be away from the Potter stuff, but it would also help space things out since majority of the SZs are concentrated at or near the front of the park except for SF.
Always felt the back corner of the event was lacking scares.