I think it's biggest crime is that it's boring. I mean sure, previous games had brutally long cut-scenes and atrocious writing but at least they were played up ironically and the all batshit insanity that happened on screen was actually fun. MGS4 is just a slogfest, both in gameplay and cut-scenes.
It's a badly written, badly edited, overly wrought, boring movie with few gameplay segments randomly thrown in.