#2 Roman Reigns
Roman Reigns debuted in WWE as a heel alongside Dean Ambrose and Seth Rollins as a part of The Shield. Since the group broke up, WWE has been trying to set Reigns up as the top babyface of the company. The WWE Universe hasn't been kind to him, and he gets booed nearly everytime he steps into the ring.
The spot for the top heel in the WWE is still vacant. Roman Reigns is set to face Brock Lesnar for the Universal Championship at WrestleMania 34. Now just imagine, Reigns wins the title - with the help of Paul Heyman! This way one gets to see the Universal Championship every week, and you get a new big bad heel in town.
Let's face it, someone who "retired" The Undertaker at WrestleMania cannot remain fan favorite as a face. Quit pretending he’s some kind of a likable underdog, and cut him loose as a dominating, cocky, and ruthless monster.
Roman has failed to find traction as a babyface, and a much-awaited heel turn will be a fresh page in his chapter. The Big Dog is a great in-ring worker, and a heel turn is what Roman needs for him to win over those who detest him. Roman as a villain with Paul Heyman by his side on a weekly bases would be a high point every week.