Kana was also one of the girls who performed in Paris. Sadly, she failed to impress me. She didn't look happy at all and she didn't come across like an idol. However, three years later...
I think Kana is just more comfortable being in Japan. Especially being among people she knows. When she's around old Team K members she seems really lively, open and funny. When she's taking out of her comfort zone, and especially if she has to speak English, she just seems to shut down completely. As a foreigner, of course I prefer a girl who can shoot me a smile during performances abroad. As such, Kana will probably be never one of my top favorites.
Kana was one of the only girls who wrote about the Nacchan/Yone situation without falling back to standard meaningless messages, so I do respect her for writing about her personal feelings. I guess her emotional side is often blocked by her hard outer shell, but it's definitely there.