Well, perhaps part of the problem stems from thinking of it as a shooter, which it isn't, not really. Yes, there is obviously a good deal of shooting in it, but calling it a shooter puts you in the same mindset of it being Gears of War or Call of Duty, and it obviously isn't. As for his arms shaking - and wow, if ever there was a nitpicky complaint, that's one - Nate isn't a mountain climber, he's just a guy, and while he understands the necessity of climbing, etc, that doesn't mean he's not going to be scared of slipping and falling.
Ultimately, your enjoyment of the game boils down to whether or not you enjoy tagging along for the adventure. If you don't particularly like the characters or give a damn about the story, then, no, you likely won't love the game.