#5 Scott Steiner
One of the main reasons why the Invasion Angle of 2001 was such a failure was because of a lack of genuine main-event level talent from WCW. Among these notable omissions was "Big Poppa Pump" Scott Steiner, who had just freshly reinvented himself from generic technical mastermind to the larger-than-life Genetic Freak that we all know and love. When Steiner finally signed with WWE in 2002, fans were excited to see the "Big Bad Booty Daddy" whooping hi wrestlers and cutting entertaining promos on his opponents' wives once again.
And then he debuted... as a face.
A former WWE writer just went after JBL for his comments HERE
Yes, at the 2002 Survivor Series, Freakzilla debuted by attacking Matt Hardy and Christopher Nowinski, both of whom were heels at the time. He then cut a scripted face promo. Why, in the name of God, would they make one of the most compelling heels in wrestling turn into a heroic babyface? Why would they ever hand a script to wrestling's most infamous loose-cannon at the time? It made no sense, but nevertheless, WWE went with it, thrusting him into the main event feud with Triple H over the World Heavyweight Championship.
Their two matches from 2003's Royal Rumble and No Way Out PPV's were, for lack of a better word, awful. The former of the two even went on to win the Wrestling Observer Newsletter's "Worst Worked Match of the Year" award. Steiner was well past his prime, gassing early into his matches and appearing to be carrying more mass than he could handle. Not only that, his foot hadn't completely healed from the nerve damage he had suffered near the end of WCW's life. He had what was called "drop foot", which is essentially paralysis of the foot. Triple H was also healing from a partially torn quadriceps muscle at the time, so pitting the two of them together was a recipe for disaster.
After the powers gave up on Steiner, his career went downhill fast. He would go on to have a debate on the Iraq War with Chris Nowinski, feud with Test over Stacy Keibler's managerial services (why?), turned heel on Keibler and left the company after a cup of coffee in the 2004 Royal Rumble.
We never got to see Steiner truly let loose in the WWE, even during his brief heel run. For that, he gets my sympy.