No he isn't op, but he does force mixup in his rushdown which is different from most other rushdown characters. Arguably I'd say that when he goes for his stance cancels and low/counter mixup those are hard reads that can make or break his pressure. His air mobility is nothing to worry about and though he has high oki mixup potential he has to work to get in. He just doesn't have to work to stay in like other rush down characters, he just has to guess right and take risks that can end at worse with him eating a punish combo. He'll have the most trouble with zoning characters and others who present a risk up close like Faust, Zato, Ram and Pot. Those characters can keep him honest and/or play to his weaknesses.
Full screen he isn't a threat where Faust and Ram are, and it doesn't matter how tricky your rushdown is if you yourself are being mixed up Zato, Pot, Ino. Don't get me wrong though, he has the ability to fight these characters but he is by no means almighty, just learn when you can press buttons and know what you could be risking by making the choice. I'm calling it now, Whitefang is the masher's bane