I beat LOU and wasn't impressed. What gameplay mechanics make this game stand above other 3rd person shooters? Liking the story of a game doesn't make the game good. If the gameplay is shit so is the game for me (a good example is TWD). LOU is ok, but not outstanding or GOTY material.
Gameplay always comes first in a game for me and story 2nd. That's why I love the MGS series, best of both worlds.
LOU actually doesn't play like your traditional shooter. If you've played online enough you would know it plays nothing like one. You can't even step out into the open for a moment, and it is extremely slow paced. Maybe the shooting mechanics, but not the gameplay as a whole.
Also even talking about gameplay, the attention to detail in game, is truly something else. That's what separates naughty dog from everyone else, they focus on every little detail in game. You are way too focused on one aspect of the game (which is wanting it to be completely original), either that or you expect a sandbox game, which it isn't.