Shadowmancer
I am The Last Baron
To be fair this is only the ones that were released for no real reason or who asked for their release or let their contract run out. So that means that Angle, Christian Cage and Chris Jericho aren't involved in this equation. And to narrow it down, lets say from Wrestlemania 21 through to Vengence 07.
My pick is Muhammed Hassan, he got the most heat for his gimmick at the time, they had him work with HBK they got Hogan to work with him and Daivari, The only reason they released him was because of the Smackdown incident where they had several masked assailants beat up Undertaker this was just before the London Bombings, He then gets demolished by the Undertaker, sent back to development and then was quietly let go. All because UPN didn't want that kind of gimmick. IMO he could have been one of the Top 3 Heels and quite possibly in the title hunt right now without injuries. He had the In-ring skills, he had the look, he had the Gimmick, he could have been a big deal.
My pick is Muhammed Hassan, he got the most heat for his gimmick at the time, they had him work with HBK they got Hogan to work with him and Daivari, The only reason they released him was because of the Smackdown incident where they had several masked assailants beat up Undertaker this was just before the London Bombings, He then gets demolished by the Undertaker, sent back to development and then was quietly let go. All because UPN didn't want that kind of gimmick. IMO he could have been one of the Top 3 Heels and quite possibly in the title hunt right now without injuries. He had the In-ring skills, he had the look, he had the Gimmick, he could have been a big deal.