#4 Aleister Black
Just like Ricochet, Aleister Black has megastar potential. He has all the tools to succeed, including a really good character. Black is a unique superstar whose aura just engulfs an arena, dare I say - like The Undertaker. They both have that demonic persona which does well on the main roster.
However, Black lacks the size of The Undertaker, and he certainly needs to bulk up in order to avoid getting sent to 205 Live.
Black could get lost in the shuffle from time to time like Bray Wyatt, or he could become one of the greatest characters in WWE history. He needs to be the cunning, quiet, and ass-kicking badass superstar he really is.
Having a unique look certainly helps him in the eyes of WWE management, as well as the casual fans. But knowing the WWE Creative these days, they could easily destroy Black when he gets to the main roster.