Before anyone else does so, let ME give MY infinite wisdom on this matter.
Matt Hardy was clearly one of these guys.
Edge has stated he wants to retire after his current deal expires.
Rey Mysterio has also said this.
MVP is reportedly not happy with his position in the company.
The 5th guy could be anyone. Chavo, Masters, JTG, Yoshi Tatsu, Primo, Zach Ryder and countless other underused talents have reason to want to leave.
Now THAT, is infinite wisdom!