4. Jane Foster Didn't Die
I think everyone was certain that someone who was close to Thor in some way was going to die in this movie. Loki, Odin, Frigga, Jane Foster, Sif and numerous other characters with whom Thor was (or had been) very close (to) were speculated to meet their demise - but Jane Foster was undoubtedly the favourite. Natalie Portman has publicly stated the fact that she dislikes participating in the Marvel Cinematic Universe movies, and fans have expressed their dissatisfaction with her character and her relationship with Thor, so it seemed like the natural thing to do was kill her off. That didn't pan out, however (and her relationship with Thor did actually develop in to something slightly more meaningful and worthwhile in this movie), and it was actually Thor's mother Frigga who met her maker at the hands of Malekith and Kurse. Of course, Loki also "died" in the movie, before returning to usurp Odin as ruler of Asgard, but the fact is that Jane Foster remains alive and played something of a pivotal part in this movie to somewhat rectify the fact that she had previously been nothing more than a pointless onlooker.