#2. EC3

EC3 has been in the WWE before as Derrick Bateman which was a flop, but don't expect him to be a flop this time. This time he has arrived at the persona he is best at.
Former TNA star, EC3 is a former 2-time TNA World Heavyweight Champion and Impact Grand Champion. EC3 announced at NXT TakeOver: Philadelphia that he has joined WWE and arrived as a heel. He fought his first match at NXT TakeOver: New Orleans, a 6-man ladder match for NXT North American Championship where he lost.
Look who just shut down all of Tony Khan's critics! More HERE.
Also, he remained undefeated in singles competition until his loss to Johnny Gargano. He is a wrestler who has charisma and mic skills second to none. He might become a champion in NXT and convert NXT into NX3 no doubt. But his skills have guaranteed that he is a future main roster champion.