#3 Randy Orton

Let's accept the fact that Randy Orton is a born heel. He knows it better but it seems that WWE is not ready to accept the fact. They have been wasting him as a babyface since his return, and he is also getting tired of being one.
In an Edge and Christian podcast, he had clearly mentioned that he is dying for a heel turn, and who can deny the fact that Orton's heel turn is what Smackdown Live needs right now. From 2006-2010, his heel run was amazing, and without a doubt the Viper's bad guy character was very much loved by the Universe. "RKO outta nowhere" is tailor made for a heel and not for a babyface.
With Orton more motivated as a heel, WWE should consider the idea of turning him to a heel soon.