Yeah, setting makes a big difference (I also think Rapture is more interesting than Columbia), but if I might say so, you're giving the first Bioshock's encounters a bit too much credit. The encounters in the first Bioshock were against relatively small numbers of splicers at a time, and took place in generally small areas. Fights ended very quickly, and to me, they felt like minor obstacles more than anything else, and they were dull as a result. That said, I'll admit that I didn't think about/care about splicers being more appropriate for the scenery.
However, in Infinite, you have more wave-based encounters, but they take place in more open areas, with some fun opportunities for traversal via skylines. I think it deserves some credit for that, and I certainly don't see many people talking about how comparatively small-scale the combat encounters in the first two games were.