I'm confused, isn't Mileena a hard counter to Baraka/stryker? Ball roll low profiles the grenades for huge damage. Without grenade pressure Baraka is honest as fuck with low damage outside of the corner. There are other moves that low profile grenades but this is the best example.
I also feel like Sindel, Reiko, Raiden, Ashrah, Kenshi and probably Johhny are all 4-6 MU's for Baraka. I'd say Lui Kang, Tanya, and possibly Kung Lao could be added to that list as well.
I also don't think it's fair to say a character HAS to have a direct counter to grenade pressure in order to beat Baraka/stryker. Sindel doesn't as far as I know but she is for sure the better character and would come out on top the majority of matches.