MGSV is safely in my top 10 solely for its sublime gameplay. I honestly think it's the best-controlling third-person action/shooty game ever made. While I would have liked another half dozen bossfights, I think everything to do with the gameplay is pretty much unimpeachable. It's fucking incredible, end of story.
However, the game is an absolute mess in pretty much every other way. I actually like what little story there is (at least in Chapter 1), but it is so poorly paced and bizarrely told. Such a huge gap of nothingness between Mission 2 and Mission 27, then the game dumps a mountain of wolbachia exposition on you in the last few missions that it expects you to listen to while also telling you it's time to go and get Skull Face. That surreal Jeep ride, the unfathomable decision to split the game into two chapters, every shitty thing to do with Quiet. The hubbub over dropping Hayter for Sutherland because they needed a proper actor for their new facial capture, only to find out that Venom never spoke or moved his face anyway.
The Peace Walker grind came back with a vengeance, now with a few dozen more hoops to jump through to watch your progress bars fill up. Side Ops were reduced to cut & paste 'Extract Soldier #27' and 'Eliminate Tank Unit #19', while what used to be Side Ops were integrated into the main story with zero context. "Boss, blow up some tanks for fifteen minutes because I guess Cipher might be behind it or something". Why would you set Mission 43 during another parasite outbreak instead of having you do it during the first one when the revenge plot actually means something? What happened to this fucking game?
Mission 51 wouldn't have saved anything; it's one subplot wrapped up in a game where the main plot already came to a wet fart of a conclusion twenty hours earlier. I'd still absolutely love to know what this game might have looked like if Kojima had actually finished the whole thing, but for all we know that could have taken him another five years.