#2 Sheamus
Sheamus was once considered a top babyface prospect and even though he's had an amazing career in WWE, he didn't quite become the 'next John Cena' which WWE had hoped for.
Sheamus is still one of the most decorated Superstars of the modern era. He's a 4-time world champion, 5-time tag-team champion and a former Royal Rumble winner.
#1 Ryback
Ryback was all set to break out as a huge babyface but something went really wrong somewhere along the line. Ryback was mowing down anyone who stood in his path after his debut and quickly gained a 38-match winning streak with comparisons to Goldberg obviously taking place. He was also being called as someone who could steer the company in the post-Cena era.
John Cena himself put Ryback over during his feud against CM Punk but this was the peak of Ryback's career in WWE. He seemed like more of an afterthought following this and his terrible heel turn did not help.