This is undoubtedly going to be the most polarizing game in the series, even moreso than 4. Guns of the Patriots, for all its issues, was still a dyed-in-the-wool Metal Gear Solid game. You sneaked around, you collected stuff, you called people, you watched insufferably long cutscenes full of ham fisted dialogue with varying degrees of charm. It's my least favorite in the series, but it's absolutely a Metal Gear Solid sequel in every way. The reasons I dislike it are almost entirely related to what it does with the story - and I really mean "what it does," because MGS4 does a lot. I don't like it, but there was a lot there.
MGSV is weird because it doesn't really feel like a Metal Gear Solid game in story or in spirit. That's not a bad thing, by any means - I've basically been doing nothing but play the game since it came out. It's really fun. The freedom you have over every situation is mind-boggling. It's like I'm playing the true sequel to Crysis or something. I love it. I will probably continue playing it and keep returning to it over and over, because it's seriously so refreshing to play an action game that just lets me do whatever I want.
But whenever it goes out of its way to remind me it's a Metal Gear Solid game, it fumbles. The story is practically nonexistent, and what's there is confusing, barely thought-out rubbish. Characters feel like they're there to tick boxes, not contribute to a narrative. Why is Ocelot there? Why is Huey allowed within 100 miles of Mother Base in the first place? Why is Eli Liquid, and why does this look into Liquid's history make zero fucking sense if you know anything about Liquid at all? What's the point of the Big Boss twist? Unlike MGS4, which took a lot of familiar pieces and moved them in ways some people liked and some people didn't, MGSV's script just feels like it grabbed a handful of pieces out of the box and did nothing with them.
So yeah, even for me, it's polarizing. Ultimately, this is probably the most fun I've had with a Metal Gear game in terms of just, I dunno, sitting down and playing the game. I seriously can't overstate how kickass the game itself is. But then there's the context of it being Metal Gear, and stuff like the repeated missions and clearly missing story stuff... yeah, people who are into MGS for the story and only the story are going to have a fit over this game.