Ken's draw backs have never had anything to do with him being undiciplined, the only thing holding him back is him having a life away from fighting unlike Ryu and many other Street Fighters. Ken is said to be just as capable as Ryu, but he's always chasing him because Ryu does nothing other than fight while Ken is always having/choosing to take care of his family, and his family business, as well as galavanting across the globe fighting in tournaments.
I have to say my knowledge on Ryo is a little lacking, which was why I only said I was leaning in Ken's direction, but from the little I know, Ryo hasn't won the kinds of tournaments that Ken has.
Good points. And with that, I should have said distracted as opposed to undisiplined. Ryo is plenty strong and fast, though. He has a plethora of different types of moves that will do him a great deal of service here, both up close and at distance. Not the least of which is the Heaven's Glaze Fist... Ken is a soldier, but Ryo is a beast when it comes to training, only entertaining the occasional date with his long suffering girlfriend, King.