Both before and after the end of Extreme Championship Wrestling, a lot of top wrestlers from the company were signed by WWE. Some, such as Mick Foley, Rob Van Dam and the Dudley Boyz, among many more, would go on to have huge and prominent careers working for Vince McMahon, however many were not so lucky.
This wasn't their fault, WWE just didn't know what to do with them, despite being so talented. There have been many over the years, but here are, in my view, the top 10.
#10 The Public Enemy
'Flyboy' Rocco Rock and Johnny Grunge were paired together by Paul Heyman during the early days of ECW after he had seen how well they worked as opponents elsewhere.
As a tag team, they excelled in ECW's hardcore environment, competing in highly entertaining brawls. They had many memorable moments in ECW including being buried in the ring by every fans' chairs in 1994 (the first of many times this happened in ECW), and towards the end of their run with ECW, The Public Enemy asked the fans to come into the ring to dance with them one last time, to which so many did that the ring collapsed. When it was all said and done, they were four-time ECW Tag Team Champions.
After leaving ECW on bad terms and being verbally buried on the air, Rocco and Johnny negotiated with both WWE and WCW, with publicly choosing WCW, where they wrestled for just about 2 years and had a one week run as Tag Team Champions. They then finally arrived in WWE, for a short and horrible run. Most WWE bigwigs, particularly locker room leaders like the APA were very unhappy about the P.E choosing WCW over WWE, and were beaten up for real by the APA during a match. The APA claimed that they "ran The Public Enemy out of the WWF''.
Now to be fair, Rocco and Johnny were not exactly the best performers in the world, in fact, they weren't that good in the ring unless it involved a lot of weapons, so it's not that hard to understand why they had a poor run in WWE. However, this was at a time when hardcore matches were a must on WWE TV every week, so if the Public Enemy just stuck in those ranks, they probably would have had a little more success.
Sadly, Rocco Rock died after suffering a heart attack following a wrestling event in September 2002, and Johnny Grunge died in his home after suffering from complications from sleep apnea, in February 2006.