I have to fully disagree with you on that, After having a run through of Bioshock Inf and watching the overall story line of it, it's by the far the best Bioshock. I didn't enjoy Bioshock 1 and 2 at all, then I was introduced to the 3rd installment of the series and completely drooled over the game.
It has impressed me thus far and I will get my hands on it for Xbox when I have some spare pocket change lying around.
I agree with Graal, very disappointing game.