2 different versions of Hulk Hogan (1980's Hogan, Current Hogan) were originally meant to be in the game. It seems they were removed later in development, as they both have select screen photos. the reasoning behind their removal is most likely due to Hogan's termination from the WWE during development of the game.
The Ultimate Warrior was originally going to be in the game. It seems that he was removed later in development, as he has a screen selection picture. The reasoning for his removal is due to James Hellwig (Ultimate Warrior) threatening the WWE with a lawsuit.
Jeff Hardy was originally a playable character in-game, but was later removed. His removal was late in development, as he was featured in one of the game's trailers. His removal from the game was most likely due to his contract termination from WWE during development.