Shells do not make an open world. You should be able to enter buildings and interact with the objects inside them. In Magnolia Promenade there is a little Chinese takeaway shop in one of the shell buildings, I think they could have made that into an interactable object. Same with San Myshuno, they could have added some shell shops in some of those back alley streets you can visit, because cities need lots of shops, businesses, and cafes. I don't want a world that is full of shells because they take up as much space as an open lot would, and in the end they are just shells with limited playability. But, I agree, if they add shells on the edge of the neighbourhood, they should definitely add some interactive elements to them.
