Tauriel could have been better, in my opinion. I think the character was useful, given the changes Jackson has made to the film and the extra ties to Lord of the Rings, having a sympathetic-to-the-dwarves elf is a good idea. And Legolas obviously couldn't do that. I am completely in favour of adding a prominent female character to the cast, since this is a bit of a sausage fest. But... yeah, I agree with Ireth, she was very poorly handled. She doesn't get to do any fighting on her own, really, despite being the captain of the guard. It was almost always tag team archery with Legolas. Instead of having her use healing magic, I think she should have been fighting the big bulky orc and chasing after him on horseback. I was okay with her liking Kili, but having Legolas like her on top of that? A bit too much. Particularly when he decided to defy his father to go follow her - would have been better if he shut the gate on her. Her healing was a bit Mary Sue-ish, but at the same time, she didn't really get to do anything or add much. She didn't tell the dwarves what herb was needed to heal him, she didn't fight her way through an army of orcs to find it, she just arrived - saw the herb that would have healed him anyway - and supplemented it with a bit of elven magic so Kili could think she was pretty when she glowed. It's like she wasn't enough of her own character, yet she was still kind of a director darling despite that. A really strange combo.