Whitney had way too much of that song handed over to her. Kim had a ton more range to show in the song, however--and I would have loved to her more of her take on the song.
Why do they keep saying they put strong singers together? Heck, put whoever you think is strongest with a weaker singer and that way more of the stronger singers will get through.
At least Adam had the common sense to pick Kim, because she definitely out sang Whitney, despite getting less solo work. Nice that Whitney acknowledged how hard Kim had worked and said she deserved the win, however.