The reason for the 7.9 is that it knocks it out of great territory and into good territory , he even mentions as much while narrating it.
Basically, combat is awesome but grows a bit tiresome given the games colossal length, the puzzles are too often so obtuse it's impossible to figure out what to do , the controls for everything other then fighting aren't as perfect as they need to be leading to all too many cheap deaths and too much of the game is spent wondering what to do and where to go next.
Sounds like a bloated hollywood film, as if they could have somehow hired an editor to shave off 30% of the game and cleanup what was left it'd be a better experience.