#3 Sami Zayn
Sami Zayn is signed with WWE on the SmackDown Live brand and debuted in 2013. His debut in NXT would eventually lead to an NXT Championship reign after defeating Adrian Neville. Furthermore, Zayn's time in NXT would cement his popularity with the WWE Universe.
In recent months Zayn would turn heel by assisting Kevin Owens to defeat Shane McMahon in their Hell in a Cell match. Consequently, this would lead to a rivalry between, Zayn, Owens, McMahon and Daniel Bryan.
Their rivalry will culminate at WrestleMania 34. Therefore, with Zayn embroiled in a heated rivalry and his career on the line should he lose, the prospect of becoming WWE champion seems distant.
However, considering the draft usually follows WrestleMania, the options are still lucrative. Moreover, Zayn may yet still win at WrestleMania. Summarily whatever decision WWE has for Zayn, he certainly has credentials to be WWE champion in 2018.