Regardless of whether he's normal or Shin, this match goes to Akuma. He has more options when fighting at a distance compared to Devin Jin and greater speed as well thanks to Ashura Senku. And considering Devil Jin is walking evil, he'd get a pretty brutal death from the Shun Goku Satsu.
Devil Jin could fly, but his options in flight would be quite limited from either flying in with attacks or attempting to fry Akuma with his laser eyes. With the time it would take for him to prepare such attacks, Akuma would have enough time to easily evade them. Flying in would be suicidal since it would leave Devil Jin open to a counterattack and Akuma's fighting style is pretty much specialized in delivering quick death to his opponents.
Keep in mind Akuma in his regular state is him not using his full power. The guy intentionally doesn't use his full power because it would end matches prematurely and he doesn't fight with his full potential so he can give fighters he deems worthy to fight him a fighting chance. Devil Jin is Jin completely consumed by the Devil Gene thus Jin is as powerful as he can get in that form. If Jin's at his peak for power and Akuma isn't, then I have to see Akuma as the victor here.
AKuma should own him, Streetfighter is on a higher level of combat and far more energy intensive. Tekken is too realistic to compete, too slow, too weak, and not enough energy wielders, it's a different world and devil Jin might be tough in that world but Akuma would Instant Hell Murder him in less than a minute.