#4 Kevin Owens
The former Universal champion is one of the biggest stars in the company right now. He has proven his mic skills and in-ring ability multiple times in his career. Had he been on the stage a decade ago, the fans could have seen some great storylines involving him and names like Edge and Randy Orton at their peak.
WWE was looking for their future star at that time. This could have well suited him with workers like CM Punk, Cena and Batista to go against and with skills he has, he could have become a major face in the company. He is one of the best heels in the company right now and could have achieved a lot at that time. Currently, he is generally involved in random feuds and is unclear if WWE will put a major title on him anytime soon.