4. Eddie Guerrero
WWE.comThe late, great Eddie Guerrero was a guy who never got his due until very late in his professional wrestling career. Toiling away as one of the 'Vanilla Midgets' in WCW, he made his name alongside guys like Jericho, Benoit and Malenko in that promotion's fondly remembered cruiserweight division. Guerrero was actually one of the first to jump across with some of the other aforementioned WCW talent, just before the merger in 2001, but despite his incredible skill and charisma, he found himself once again working away on the midcard. He'd stay there until 2004 where he got a break seemingly out of nowhere for the WWE title and finally became WWE champion just before Wrestlemania, defeating Brock Lesnar at February's No Way Out PPV. This was during a time with two titles however, and the WWE title Eddie had won was secondary to the World Heavyweight title in terms of prestige. This meant Eddie's first title defence at the following month's Wrestlemania XX would not be the headline match. Instead, longtime friend and running mate Chris Benoit would defeat both Triple H and Shawn Michaels in that main event, winning the World Heavyweight title for the first time himself. After a run with the title throughout that year, Guerrero lost it before the following year's Mania, which would be his last ever. He passed away in November 2005, never getting another chance at a 'Mania main event. His death is perhaps the sole reason he never got that opportunity.