It's true that the story felt weak, not only because of the game's small number of cutscenes, but also because these cutscenes were pretty much all used in the trailers. Gameplay wise though, I think it's perfect. I have never seen an infiltration game or even an open-world game with that level of polish (I would compare it to Nintendo polish but that's my opinion). Anything you want to do is doable.
And come on, the game isn't repetitive. With that level of freedom, it's impossible. You just have to find different ways to play, the game was designed around the idea of changing your approach.