I think it all boils down to it not feeling like a legitimate Metal Gear Solid game. It feels like an impostor (hehe). Sure the gameplay and graphics are great, but it's not Metal Gear in the traditional sense. Where's David Hayter? Why so little dialogue and cutscenes? Where are the ridiculous boss battles? Where's the epic finale that every other core Metal Gear has? These are staple things in MGS that make it so unique and sure some don't like those aspects of the classic MGS's, but guess what? That's what makes Metal Gear Metal Gear. You either love it or hate it, but once you completely change the formula don't call it Metal Gear Solid.