Originally Posted by 04nbod
I don't think it actually did. The big theme was grounding magic as Science, without Jane that disappears. Without Jane and her entourage there is no real plot once Thor is banished to Earth, and its only on Earth Thor displays any character at all beyond bloodlust and arrogance. Jane is the only character besides Loki and his father that Thor significantly interacts with. Jane is the everywoman perspective for the viewer, she's the human angle. There is no other character from Thor's history that can fill that role considering they've thrown out the Donald aspect where Thor himself is human and relatable. Jane does more in this movie than even Odin does and has a more nuanced character arc where she has her mind opened to the fact that all these crazy things are possible, that she is right and her theories are going to change the world.
People say she's underwritten and its true which is why I expect more in Thor 2 and not just dropping her and trying to start again from scratch while throwing away everything you have done.
And her function is done. You could easily have Thor come to Earth again for another purpose entirely, not even mention or see her, and nothing would feel unfinished. Oh...she was a 'love interest'. Right...how memorable was that?
Technically, sure you could point to how important she was in the actual plot, yadda-yadda. How did it feel, though? Was there electricity? Like we have to see where the relationship goes or something will feel lacking? That's why she's interchangeable.