I still think Frost had the more interesting appearance. Just out of nowhere she comes out and attacks Scorpion. The image of her before the game was released had so many people scratching their heads trying to figure out where this came from, who modeled it, or if it was from the mobile.
Her comic appearance was also interesting, almost kicking Cassie's ass to defeat but of course, people portrayed in an evilish way HAS to have a monologue before getting their ass kicked.
I will say, I think she is either the second or third most wanted female character to become DLC. I can't tell if Sareena has more wants but I've been told that people have recently just jumped on the Sareena bandwagon or whatever.
Frost could be cool to see, and I would be happy to see her more than anyone else but it's really whatever. With Sareena, I'd like to see the other assassins more than her. I have just never really been a fan of hers. Still waiting for them to finally show us her demon form that I feel like we'll never see... ever.