#7 Corey Graves
When it comes to talking about wrestlers who had potential, it is impossible to leave out Corey Graves. Now one of the best heel commentators in the company, Graves was supposed to have a huge career in the ring as well.
He was in NXT during the time of Seth Rollins, Roman Reigns, Dean Ambrose and Bray Wyatt, but while all the rest went on to achieve success this was not on the cards for him. Graves had amazing matches with Rollins and Neville, but he also suffered a number of concussions.
He would return to television on the pre-show panel and announce his retirement due to concussion issues, and though this was heartbreaking for him, he never really showed it. He went on to become possibly the best modern commentator in WWE, and works on both Raw and SmackDown at the moment.
This may be his only consolation when he thinks about all that he could have achieved in the ring, but he was never able to.