I saw Krystal and didn't like her all that much...
1) I think she must've been sick, because she was really raspy. I personally don't like it when they cast actresses who sound like they have vocal damage. It's painful to listen to, though it does sort of fit the character.
2) She was too tough. I think Mimi is a very vulnerable character at heart...I like to see that.
"A little humility wouldn't hurt."
--Ellie, Constantine-Hellblazer, "Dangerous Habits"