#2 Finn Balor
Finn Balor seemed poised to be the next big thing. Drafted from to Raw NXT before wrestlers like John Cena, Roman Reigns and Brock Lesnar, he also became the first ever Universal Champion. However, a shoulder injury derailed all his momentum instantly. His return from injury seemed so promising, and he seemed primed for another push and a match against Brock Lesnar eventually. Vince McMahon nixed that plan, and essentially gave Balor the dark mark.
Even though Balor is exceedingly talented and can do whatever is asked of him, he just will never get over the blow delivered to him by Vince McMahon. Being squashed by Kane, and no commitment to his character from the creative team, it seems Balor will always be one who reaches for the ring but can never get his hands on it.