I really want them to up the ante with the storytelling. Whatever they do, it needs good writing, foreshadowing, intrigue, recurring bosses and the like.
It should show us a villain 3 hours before we put it down. Build anticipation on characters, allow for them to grow, bring in some centuries spanning undead mumbo-jumbo and all that.
Once again, imagine what Kojima could do in an environment where any crazy idea he has can be perfectly justified and then built 3 encyclopedias of backstory on.