I'm going to preface this by saying that I understand I'm in the minority here and it's totally cool if people disagree with me, I'm not here to yuck anyone's yum. I am curious to see if anyone agrees with me and the kind of conversation we might be able to have discussing this mechanically.
Metal Gear is my favorite series. I have played every game in the series, even the turn-based card game PSP spinoffs, the non-cannon Game Boy Color game, the mgs2 skateboarding mini game. I've played most of these games many times.
I hear it repeated ad nauseam that Metal Gear Solid 5, despite its limitations in story, had "the best gameplay in the series". I hear this repeated as an uncontested fact so often and I hate it because I think it has some of the worst gameplay in the series.
Metal Gear Solid 5, undoubtedly, has the strongest of the three C's : Character, Camera and Controls. In terms of just moving snake around it controls incredibly well, it's responsive and satisfying and all of that is terrific. If that character controller was put into a game with great level design it would be one of the best stealth games ever.
The problem is everything you actually do in the game, its structure and progression.
The game sacrificed tight stealth game levels from the previous games for big open sandbox design that feels like it could have been generated by a script. Instead of presenting you with a set of tight levels that are constantly evolving, you're infiltrating dozens of samey bases over the course of the game. The different bases rarely require new approaches to stealth, the same core tactics that you can utilize at the start of the game remain incredibly efficient at the end. Even when guards start resisting certain tactics, you're constantly developing newer and more powerful tools that just delete enemies. Once you get an idea of how the AI works you no longer have to engage with the level design, every level feels the same.
Compare this to the first three Metal Gear Solid games. Those games are short and sweet, each one only has a few hours of gameplay, but it never repeats itself. Every room is different, they're constantly throwing new hazards and combinations of threats at you. I can play through Metal Gear Solid 3 in my head because every second of that game is unique.
The progression systems in MGS5 strip the open world of any real value and exploration. You're not really finding items that change things, you're just increasing your number of one of several generic resources. The entire process of expanding your Arsenal is offloaded to the mother base system which is time consuming and grindy. Kidnapping hundreds of personnel over the course of a playthrough just so that you can develop the newest versions of the same five different tools that you're going to be using throughout the whole game.
Metal Gear Solid 5 feels like a really great 10 to 15 hour long game cut into pieces and spread over an incredibly boring and repetitive 50 hour long game. Most of the content is incredibly generic and repetitive, and while there are a few sequences that are truly memorable they are few and far between.
I would much rather have a 10-hour long game that is dense with polished and unique content then a 50 hour long game that never really evolves or changes as it goes.