I'm terribly biased here, but my opinions:
@rikaquegira, I don't have statistical evidence either, but I've yet to see a Korean lady being called on a flutz, I've seen a lot of !s on flips though. I call it the 'pioneer syndrome', since our Queen basically introduced the country to figure skating skaters after her tend to take on her traits. Like, in rhythmic gymnastics, current gymnasts show a lot of similarities in style with Son Yeonjae, the first rhythmic gymnast to break out into the international scene. Just my theory though.
I love darling squirtle to no end so I may not have the most objective eyes, but you just have to look at her SP to know that Eunsoo's style isn't just limited to 'sassy' or 'flirty'. She does have the ability to project and express diverse characters, it's just that from what I've observed, she's yet to have thought to spare when she's concentrating on jumps. And she has drastically improved from last season, her spins, body movements, expressions, the list goes on. Give her time (and a program that is not choreographed by Suzuki Akiko...), she'll bring out her full potential. Also, I wouldn't call her inconsistent, she's yet to clean on her FS, I know, but she was very much consistent as a junior, which she has just come up from this season. I say it's most likely nerves, she's not one with nerves of steel.
Yelim also has been consistent from what I've seen of her, and she has kept on improving on everything. Her SS need to get better and her spins could use some work, but I disagree with the statement that she lacks emotion. Her style is light, airy, and delicate, her eyes are where her emotions show. And although I'd like to see more sides of her (and she does need to develop them to become a mature skater), her thin frame and quiet composure is best suited to that style. I personally prefer her with programs that suit her than new, different programs that don't, so I'm not rushing her into suddenly developing a new persona. She'll do as she does, facial expressions and all.
Young is the most performer-like of the trio, I have zero worries about her lacking performance-wise. Just look at her FS, while I don't think her personality fits Eliza, she was always charming and devoted even when she fell (and broke my heart...). Her consistency is what worries me, she's been plagued with underrotations and misses on her jumps, and she's the one who's training 3As. But she is the youngest of the trio (Yelim is a month older than Eunsoo btw, order goes Yelim '03 January>Eunsoo '03 February>Young '04 May), and she's been suffering the media hailing her as the next Queen. That is no burden a 14-year-old should bear. I'm being patient on her, she's one determined lass.
Overall, I'm sure that all three of them have bright futures ahead of them. They'll improve on their own paces, and I'm frankly thankful that they actually exist in this country with nothing but a terrible fed and mediocre infrastructure. (Slightly off-topic, but I hate how too many people here dismiss the girls' achievements just because the Queen used to win everything. Yuna was a literal once-in-a-century miracle, you can't expect everyone to be like her, goddamnit.)