I think a combination of both is best, like Peace Walker but more focused on in-doors environments, corridors and stuff like that, less open world but still some.
As for core gameplay mechanics, I don't see them getting any better.
For story, just ****ing close the circle and remake the MG games, I don't care that they don't rely on themes, just finish up the narrative with a well written story and dialogue.
I wonder what would be better, a western director or a Japanese one, Konami will probably get a Japanese director, I'd like Kiefer to Return as BB, and Hayter as Solid.
I also wonder if Shinkawa would return without his bro.
I actually think Kojima's directorial skills are at his very peak, cinematography, acting direction, dialogue, are all so slick and stylish in the game, without mentioning scenes like the jeep ride with Skullface, cardboard Ocelot, and the obvious fact that the story is incomplete, of course.