I liked bioshock 2 over the first. If you call bioshock 2 repetitive, you'd have to admit that bioshock 1 is more repetitive. There's next to no backtracking, and much less (I can't actually remember any) of that ~spend half an hour going all over the place to proceed 30 meters further into the map past some arbitrary blocked area~ stuff. Sup arcadia.
I understand why it might be called just an expansion pack to Bioshock 1, but that's the entire point - it's a sequel, you're going back to the same place. Of course it's going to be similar looking, it's not like they built half of rapture different. They removed my gripes with the first (can't use plasmids and weapons at the same time), annoying and more tedious/boring puzzles.
I also can't imagine another genre working in that setting better than FPS.