that's a great thing, not every game needs a multi player mode, bioshock 2's campaign suffered greatly because of the multiplayer, if devs feel that multiplayer modes are needed then they should do like EA did for Dead Space 2, or 343 did with Halo4, and
put it on a second disc
MP on BS2 actually was pretty fun. It sucked at first but after I started playing it more I really got into it. I was mostly playing for the level 50 achievement but ended up enjoying my time spent. With that being said, not every game needs MP and I'm glad
they scraped it in this game so they could focus purely on delivering a kick you know what experience!