Exactly. I feel the same way. I know you may disagree with me on the following, but MGS4 gave me the scene with Ocelot taking control of the world's armament in the Volta. It was a scene where he basically became the "military god" of the world. Weapons acted upon his command.
Peace Walker gave us that scene with NORAD going apeshit and Peace Walker drowning itself in the ocean to stop the data transmission. And we also got one of the best scenes in the series: Big Boss finally rejecting The Boss' way of life by first saluting her sacrifice, then hesitating, and finally throwing away his bandana which was a memento of her former Master.
MGSV simply cannot compete against those moments.