"game"
If anything one of the complaints levied against it right now it the lack of cutscenes and exposition. Fucking nerds can't make up their mind.
"Not enough game"
"Too much game"
"My eyes are dry"
(Image removed from quote.)
MGS has a diverse fanbase. It's pretty simple.
The MGS fanbase can be divided into multiple categories:
1. Those who play for the experience and just play it once, and then drop it. These people treat MGS like any other game and are there for experience of it. These people tended to enjoy 4 highly and seem to be the bulk of MGS' audience.
2. Players who are into MGS for the story and plot and characters almost exclusively, or if not that, it's still the main draw for them. They tend to replay every few years or so for story, but never for new gadgets, unlockables, and whole shebang. These are the players that mostly got something out of MGS4. Since they primarily play for story, and MGS4 was insanely story-focused to a fucking stupid degree, they got enjoyment out of the game.
3. Players who are completionists. These are the players who beat the game on normal first, then replay it on normal or hard mode but with a specific Fox Ranking in mind. They may want to complete the game without any kills and no alerts, or they may want to kill everyone, or maybe the're playing for speed. Then they go from mode to mode to mode and unlock everything, trying to beat the hardest modes in 3 or so hours, skipping cutscenes along the way on each replay. These people (aka people like me) hated 4 because the fact you have to install every chapter made speed running impossible, and the game has too many fucked up forced story areas that are completely unskippable (like that one part where you follow that guy in Act 3 while dressed up Snatcher style) so speed running is tedious anyways, even with the installs fixed. The noticeable lack of gameplay is a huge black mark on the game. This doesn't mean that completionists don't appreciate MGS' humor or zaniness or characters (I especially do) but 4 took it to a fucking dumb ass level. See Positive's post above as an example.
4. Those who are all three.
The MGS fanbase is pretty diverse and we have multiple people playing these games for seemingly COMPLETELY different reasons or if not that, they enjoy different things about them in a different manner.
The fact the story/cutscene fans are getting shit on in this entry is pretty

and makes me want to buy this game on day one just to support their tears and them fueling Kojima into making such a travesty of a game after a gaming masterpiece in Metal Gear Solid 3 and 2 Substance. Fuck MGS4 fans. I don't care. Fuck them.