How much did you play, and have you read the thread? It's been said time and time again that you have to give the game some time before things start to really pick up, both game-play (amount of player freedom and possible variations to tackle a mission, mission diversity, buddies, developing equipment, expanding mother base, recruiting and deploying soldiers, FOB invasions, etc.) and also story wise (well, with like any story it needs time to develop character arcs, progress themes and narrative, etc.).
You have to remember that the MGS receives a lot of flak (especially after 4) for unnecessarily convoluting the story too much and making it near impossible for newcomers to pick up n' play, and this entry dials back on a lot of story elements to make it more appealing/accessible (most of the story is told through completely optional dialogue tapes like most modern games). It's not a bad story per say, just not what people (should say fans) were expecting, without going into spoiler details. It's still presented fantastically with a certain Kojima cinematic flair.