So much was expected from Yamcha from the during both the Dragon Ball and the start of the Dragon Ball Z series. He was one of the strongest fighters in world and was positioned as being nearly Goku’s equal. Then he died.
Seriously, when Yamcha was blown up by the Saibaman during the fight with Nappa and Vegeta, he was never the same. Sure, other fighters would die during the conflict, but Yamcha couldn’t even make it past the minions.
For the remainder of the series, Yamcha would kind of, sort of, just be there. He was never seen as a viable threat, and he was usually the first Z-fighter to be defeated in battle.
Drew McIntyre re-debuted with too much hype in 2009, as Vince McMahon himself proclaimed him the chosen one. For roughly one year, McIntyre would find himself firmly entrenched in the Intercontinental Title picture, even holding it for a period of time. Then his visa expired.
Like with Yamcha, when McIntyre returned to the states after his short absence, he was never positioned the same. Sure, he was still a heel, and he even won the Tag Team Titles once, but he lost all of his momentum before being relegated to the lower midcard and making appearances on Superstars.
Another similarity between the two is their long-term relationship with women. Yamcha was involved with Bulma for years before she left him for Vegeta. McIntyre was married to Tiffany before he lost her due to her being nuts.