Nail Yakupov is universally viewed as the biggest "bust" of the last 25 years. Yakupov was selected 1st overall in the 2012 NHL Draft by the Edmonton Oilers and came with high expectations. In his junior hockey career Yakupov played 107 games and scored 80 goals, while adding 90 assists.
Unfortunately Yakupov never found the same success at the NHL level and saw his career fizzle out after just 350 games. Yakupov only managed 62 career goals, with 17 coming in his rookie season. After his NHL career ended Yakupov returned to play in the KHL where he has spent the last 6 seasons.
While it is incredibly difficult to make the NHL, it is even more difficult to make a comeback to the league after years away. According to reports since returning to the KHL, Yakupov has worked hard to improve his compete level and round out his game, but there is no way that will translate to the NHL.