Veelk, I don't think that it is completely fair to weight a game's story against the expectations you had based on pre-release marketing... and I had no issues with the city (maybe it looks bland in consoles?) or the grappling hook (which in fact seems to latch from a much greater distance now), but I agree with the rest of your review.
Even if I don't look at the marketing, Deathstroke's appearance and exit is still pretty unceremonious. Them marketing him as THE rival just makes it sting a bit more. Villains, especially top tier guys like him, deserve more fanfare than randomly dropping in and getting their ass kicked.
And maybe the grappling hook was fixed in the patches? I don't have much of an internet connection on my xbox where I am. I don't know if the distance is longer, exactly (if it is, it's kind of negated by the fact that everything is so much bigger) but the stupid thing just doesn't take me where I want to go half the time. Even if it should because I'm right next to it, pointed at it, and within it's range. It was extremely unreliable for me.