Ultimately, the story isn't the thing in MGSV, or at least not the one that Kojima wrote like a funhouse for you to weave your way through. No, the real story is the one you make yourself as you play through each mission, making new decisions each time and writing an action thriller of your own making. That's what makes Metal Gear Solid V brilliant, and that's why people will still be talking about it years from now.
There is an incredible amount of content across all four games, and having that much stuff means you can basically play it in any way you like. Further, every single aspect of the game is unlocked at launch, every map, every level, every upgrade.