Kyuhyun
It will depend entirely on how the general public receives him outside of Super Junior and how much pulling power he has among fans as an individual.
I guess how you might see talent is irrelevant when it comes to how they appeal to Korean audiences? I personally don’t think Hyorin is particularly pretty in comparison to all the other faces out there in K-Pop and she definitely isn’t the typical image of beauty that Koreans will have… so it’s not really her looks that are getting her popular.
On a side note, I hear her as more like Christina Aguilera, not Beyonce.