Isn't that the point?
Now let me be my usual self and go with unpopular choice.
One of the very first 5* girl back in the Nutaku day. She's far from being strongest yet I still have her in all the time because I like her open and straightforward personality. Her freckles also made her unique among the girls who usually have clean, perfect face as well. In short, her flaw make her unique for me.