As we arrive at both the 1-year anniversary of The Battle of the Five Armies and the 1-month anniversary of its Extended Edition, I think enough time has passed that we can look back on the Peter Jackson Hobbit films with a more objective eye. Whether we love them or hate them, the films have always sparked controversy among Tolkien purists, and one of their most infamous controversies is the romantic subplot involving Kili the dwarf and Tauriel the elf.
First of all, I'm not against adding an original, major female character to The Hobbit. The book has pretty much no women in it, which would be conspicuous in a modern-day film, and since many characters from the book were totally re-envisioned in the movies anyway, creating a whole new character alongside them doesn't feel like that much of a crime. When you get down to it, the biggest difference between Tauriel and the film versions of the dwarves, Radagast, and Azog is that Tauriel was given her name by the screenwriters instead of by Tolkien. I never took issue with her, just with her and Kili's romance.
Looking back on that subplot now, I'm willing to consider that it's more complex than I first gave it credit for.
While their relationship is technically a romance, it's a romance that never really gets off the ground. The whole thing is just about Kili trying to convince Tauriel to give him a chance while she keeps trying to deny that she feels anything for him. It's largely one-sided, they don't exchange sappy love dialogue, and they don't even kiss until after it's too late for them to be together. I think the reason I cringed at their relationship the first time I saw The Desolation of Smaug was because I was so bugged at the film for including it at all that I blew it out of proportion.
Now, that wasn't because Ori is an irresistible dreamboat full of charisma — which, let's face it, he's not. The reason those scenes worked so well with him was because he was so childlike that it made Tauriel's kind and protective behavior towards him come off as motherly instead of romantic. It made it seem like she befriended him in prison because she felt bad for him and then came to admire how innocent he was, not because she was attracted to him, and it made it seem like she followed him to Lake-town to help him because she wanted to preserve his innocence in the midst of all the evil that was growing in the world, not because she had fallen in love with him.
It's probably not until Kili asks if Tauriel could have loved him that she starts to wonder the same thing. Since love is unheard of between elves and dwarves and she knows how irrational Kili can be, she tries to let him down easy. That rejection obviously hurts him, but being young and hopeful, he refuses to let go of the idea. I think the reason why Tauriel's so sad at the end of their goodbye scene in The Battle of the Five Armies is because she feels that Kili's only setting himself up for more heartache over her, and she doesn't want to be the thing that ruins his optimistic outlook on the world. I really don't interpret it as her being sad that she can't be with her romantic interest that she's known for one day.
Furthermore, I think that Thranduil's speech to her about how she doesn't really love Kili is supposed to be what makes her realize that she does, hence the reason why she's in such a state of shock after he says it. Not all love is romantic love; Tauriel's feelings for Kili could be anything that's strong enough to make her want to save him from Azog's ambush, and they could be anything that's strong enough to devastate her when she fails to save him. It's possible that kissing Kili after he dies is her way of admitting that her love for him could have become romantic somewhere down the line, if it wasn't already.
Bottom line, I think that Kili and Tauriel's subplot is mainly about, again, what they represent in the grand scheme of things. It's not about their relationship; it's about whether or not any relationship between any elf and dwarf is possible, and ending it with the realization that such a thing is possible is actually a halfway decent setup for Legolas and Gimli becoming friends in The Lord of the Rings. Kili and Tauriel's romance presents the idea without them getting much chance to act upon it, and then Legolas and Gimli's friendship takes that idea to the next level by having them maintain a bond after forming it. I think that Kili and Tauriel were meant to pave the way for Legolas and Gimli in the movies rather than steal their thunder.
Maybe I'm reading too much into this subplot, or maybe the screenwriters really were trying to make lemonade out of lemons with it and their efforts just took a year or two to stand out. In either case, it's nice that Kili and Tauriel's story is presented in a way that leaves it open to more than one interpretation.