Bioshock for me, was probably one of the first true "Next-gen" games. It was easily the game of year in 2007. ( barring maybe Portal and Mass Effect...) The way it combined story, shooter and a small amount of Rpg, mechanics was astounding. It was definitely one of the best games of the decade.
Although I loved the original, I don't think there should be a sequel in any way or form.
The whole charm of Bioshock was discovering the story and world, it was the joy of interacting with these new and interesting characters, it was following the story of Jack and the mysterious Andrew Ryan, going through the twists and turns of this ingenious story.
And I really don't think that, the charm of Bioshock can really be reproduced in the sequel. I don't think the game needs a sequel basically. (or a prequel as it goes)
I hope I'm wrong, I hope that 2K really show everybody and make a truly wondrous game, I just don't think this will or can happen. read