Its an important feature that is missing in OJS. I remember it was requested in the old forum and certainly had traction, it was something that one had to find a programmer to do. It would be great if journal managers can set the access terms for their journals in terms of what is available and not available. After all, they work with their constituency and are responding to their needs.
People are usually looking for information when they land on a journal to subscribe. While I can see the idea of perceived value of buffet type access, the users needs are far more important here. Offering something that is not sought after or needed does not add any perceived value, and can be quite distracting to users. It would be great if journal managers have the flexibility to offer various option for their users.